4V Cordless Tool Technical Selection Guide: Bits, Hex Keys & Tool Sets

A 4V cordless tool is a compact, lithium-powered tool — typically a 3.7V screwdriver, precision driver, glue pen or small stapler — and it only performs as well as the accessories it accepts. For buyers working through the awareness and research stage, the decision that determines whether the tool actually works on the bench is not the motor. It is whether the bits seat correctly, whether the torque matches the fastener, whether a hex key or T-handle wrench is available as a manual backup, and whether the tool set is organized so the right size can be found and reordered.

This guide sets out the technical selection points for a 4V cordless tool and its accessory package: bits, hex keys, folding hex keys, T-handle wrenches and tool sets. All product examples and specifications below come from HOTAK PRO TOOLS product documentation.

YJTS-3508, a 43-piece ratchet screw set kit: 36 pieces of 1/4-inch × 25 mm bits in CR-V6150 steel, supplied as part of a mixed 4V and manual tool package.

The Problem: When a 4V Cordless Tool Fails, the Accessory Is Usually the Reason

A 3.7V precision cordless screwdriver produces 0.15 N·m of electric torque and 3 N·m of manual torque. A general-purpose 3.7V power screwdriver produces 2.5 N of electric torque and 10 N·m of manual torque. Those two figures — not the battery capacity — define the real working envelope of the tool. The motor drives the fastener down; the manual figure is what the user applies when the fastener has to be seated firmly or released after it has tightened.

At the bench, most disappointing results trace back to the accessory package rather than the tool itself:

• Bits that do not seat. The 4V screwdriver class drives 1/4-inch hex-shank bits, and the bit must be retained by a magnetic holder or reached with an extension bar. A 5/32-inch precision bit series cannot be driven by the tool unless the correct adaptor is supplied.
• Missing sizes at the moment of need. A 25-piece bit set that omits the pentalobe, tri-wing or triangle profiles cannot open the consumer electronics housing it was bought for.
• No manual fallback. When electric torque stops at 0.15 N·m, the last quarter-turn needs a driver the tool does not contain.
• Recessed or angled fasteners. A short bit with no extension cannot reach; a ball-end hex key used at an angle can.
• Sets with duplicated sizes. Piece count rises while coverage of the profiles actually used stays flat, and the set cannot be restocked piece by piece.

The practical conclusion is that a 4V cordless tool and its accessory package should be specified as one system, from the fastener outwards.

Industry Background: Where 4V Cordless Tools Sit in the Market

Global Market Insights estimated the global cordless power tools market at USD 12.2 billion in 2024. Inside that market, Market.us describes low-voltage cordless tools — the band below 12V that includes both 4V and 3.7V platforms — as a primary segment serving DIY and light-duty household tasks. DataHorizzon Research values the household electric screwdriver market at approximately USD 1.8 billion in 2024, with North America holding a 35% share.

Two practical notes follow from this data. First, the 4V format is being treated as a platform in its own right rather than a stripped-down version of a 12V or 18V tool; Ryobi is publicly reported to offer a 4V interchangeable USB battery system, and Dremel (Bosch Group) presents a 4V home and lifestyle tool category aimed at DIY users. Second, public market data does not report 4V unit volumes separately — those numbers sit inside the below-12V band — so a purchasing decision cannot be benchmarked by market share. It has to be made on the technical criteria in this guide.

For importers, the trade classification matters as much as the market data. HS Code 846729, 'tools for working in the hand, with self-contained electric motors, others', is the standard classification used for most cordless screwdrivers and specialty 4V tools (Descartes Datamyne). Checking the code early avoids reclassification questions later in the order cycle.

How broad the 3.7V class has become

The HOTAK PRO TOOLS 3.7V range shows how wide the format now is. It includes precision repair tools (YJPS-906), power screwdrivers (YJPS-902, YJPS-912), household electrical screwdriver tool sets (YJTS-3526, 41 pieces), a two-use lithium electric nail gun (YJSG-500) and a five-use lithium electric nail gun (YJSG-501), both rated at 3.7V with 2000 mAh batteries and 25 W, and a cordless hot-glue pen (YJGG-001, 3.7V, 320 mAh, 150 °C operating temperature, 5 V USB Type-C compatible charge output, operating time of 120 minutes or more).

The selection consequence is that this class uses two different compatibility logics. Bit-driven tools are specified by shank interface and torque. Fastening tools such as cordless staple and nail guns are specified by consumable compatibility — staple or nail profile and leg length. A buyer building a 4V package has to run the correct compatibility check for each tool type, not one generic check for the whole kit.

The Detailed Solution: Six Criteria That Decide a 4V Cordless Package

1. Interface compatibility: shank, holder and extension

Interface compatibility is the first filter, because it cannot be corrected after purchase. The 4V cordless screwdriver class uses 1/4-inch hex-shank bits, and the package should include both a bit holder and an extension bar. In the HOTAK PRO TOOLS range, the YJTS-3110 impact drill and drive set includes a magnetic bit holder; the YJPS-6851 screwdriver set includes a 1/4-inch × 100 mm magnetic extension bar and a 1/4-inch × 1-inch socket adaptor; the YJTS-3545 set includes a 1/4-inch × 60 mm quick-release extension rod; and the YJTS-3148 set includes a 1/4-inch × 60 mm magnetic extension bar with a 1/4-inch × 25 mm adaptor.

Socket accessories follow the same logic. The YJTS-3547 ratchet handle set supplies 1/4-inch × 20.5 mm sockets in 5, 6, 8, 10, 12 and 13 mm, and the YJTS-3148 set supplies nine sockets from 4.0 mm to 12 mm. If the fastener is a nut rather than a screw, the socket range — not the bit count — is the specification that matters.

YJPS-906 electric precision repair tools set: 3.7V, 320 mAh, 0.15 N·m electric torque, 3 N·m manual torque, 0–220 rpm, supplied with LED lighting and multiple bit types.

2. Torque envelope: read both torque numbers, not just one

Every 4V-class tool has two torque figures, and both should appear on the specification sheet. On HOTAK PRO TOOLS models, electric torque ranges from 0.15 N·m to 5 N·m while manual torque is specified at either 3 N·m or 10 N·m. The gap is deliberate: it tells the buyer how much of the job the motor can complete and how much must be finished by hand.

• YJPS-906 / YJPS-907 (precision): 0.15 N·m electric torque, 3 N·m manual torque, 0–220 rpm, 320 mAh.
• YJPS-912 (general): 2.5 N electric torque, 10 N·m manual torque, 0–250 rpm, 800 mAh.
• YJPS-902 (three-stage): 2 N / 3.5 N / 5 N electric torque, 10 N·m manual torque, 0–280 rpm, 2000 mAh.

Speed belongs in the same assessment. A 0–220 rpm tool suits small electronics fasteners, while a 0–280 rpm model with three electric torque stages is intended for repeated driving in furniture and assembly work. Matching speed and torque to the fastener type prevents both stripped heads and unfinished joints.

3. Bit material, hardness and surface treatment

Material specification is where cheap and durable bit sets diverge. Across the HOTAK PRO TOOLS hand tool and tool set range, CR-V6150 chrome vanadium steel is the standard base material, with hardness specified at HRC 52–55 for hex keys, folding hex keys, T-handle wrenches and several tool sets, including the 50-piece ratcheting screwdriver set YJTS-3401 and the 42-piece ratcheting handle set YJTS-3402.

For impact-type driving, the material changes: the YJTS-3109 (18-piece) and YJTS-3110 (26-piece) impact drill and drive sets use S2 steel bits with a black phosphate coating, supplied in PP cases. Surface treatment should also be checked against the working environment — the YJTS-3018 set uses a nickel finish, the YJHK-3066 T-handle wrench set is offered in chrome plated or black finish for rust and corrosion resistance, and hex key sets are specified with rust and corrosion resistant surfaces.

Geometry is part of the same decision. Ball-end hex keys in the HOTAK PRO TOOLS sets work at angles up to 25 degrees, which is the feature that makes an offset fastener reachable at all. Size markings on each key (as specified on the 105221K2 and 71821D2 sets) shorten the time spent hunting for the right size.

4. Manual backup: hex keys, folding hex keys and T-handle wrenches

A manual backup is a technical requirement of the platform, not an accessory afterthought. Because electric torque on these tools tops out at 5 N·m, the tightening and loosening step is manual by design, and the manual tool sets the real torque ceiling of the package.

Three formats cover different situations:

• Hex key sets — 9-piece metric sets are available in short arm (105221K1), long arm (105221K2), extra long arm (105221K3) and long-arm color-coded (71821D2) versions, all in CR-V6150 with HRC 52–55 hardness. Torque values run from 0.82 N·m at 1.5 mm to 220 N·m at 10 mm.
• Folding hex keys — the YJHK-3075 8-piece locking hex key set (metric) and the YJHK-3347 8-piece folding set use heat-treated CR-V6150 with a folding format and a flexible angle for different occasions. They suit tool bags and confined work areas.
• T-handle wrenches — the YJHK-3066 7-piece metric set and the YJHK-3226 14-piece metric and SAE set use chamfered tips for easy entry into screws and fasteners and an ergonomically designed T-handle for greater torque. The YJHK-3226 is rated from 1.19 N·m (1/16 in) to 242.92 N·m (3/8 in).

YJHK-3226, 14-piece T-handle hex key set in metric and SAE: CR-V6150, HRC 52–55, chamfered tips, torque rated from 1.19 N·m (1/16 in) to 242.92 N·m (3/8 in).

5. Accessory coverage: profile families, not piece counts

Coverage should be measured by profile family and size range rather than by the number printed on the case. The profiles that matter in light assembly and repair work are Phillips, Pozidriv, slotted, hex, Torx, tamper-proof Torx, square, triangle, tri-point and pentalobe.

• YJTS-3545 (30 bits): 4 Phillips (PH1–PH3), 4 Pozidriv (PZ1–PZ3), 7 Torx (T10–T40), 7 Torx with hole (TT10–TT40), 4 hex (3.0–6.0 mm) and 4 slotted (3.0–6.0 mm).
• YJTS-3508 (36 bits): adds triangle (TA18, TA27), tri-point (Y00, Y0) and a spanner (SP6) to the standard families.
• YJTS-3018 (77 pieces): includes pentalobe 0.8–2.0 mm, tri-wing Y000–Y1, triangle TA20–TA30, square S0–S2, tamper-proof Torx TT7–TT20 and mini sockets 2.5–5.5 mm for consumer electronics housings.
• YJTS-3136 (25 bits plus sockets): 8 Torx, 4 Phillips, 4 hex, 4 slotted, 3 Pozi and 2 square bits, with six sockets from 5.0 to 12 mm.

YJTS-3136, 33-piece speed-fit screwdriver set: 25 pieces of 1/4-inch × 25 mm CR-V6150 bits across Torx, Phillips, hex, slotted, Pozi and square profiles, plus six sockets.

6. Case organization and restocking

Organization is a specification, not a presentation detail. A set that indexes its sizes makes each job faster and makes wear visible. The YJTS-3110 impact set is supplied in a PP case; the YJTS-3018 kit includes a durable box for storage and carrying; hex key sets are marked by size for easy identification and the 71821D2 set adds color coding; the YJTS-3506 26-piece ratchet handle set indexes 11 sockets from 4 mm to 14 mm alongside 13 bits.

Restocking is the second half of organization. Sets with a defined piece list — 18-piece and 26-piece bit sets, 20-, 26-, 29-, 43- and 77-piece tool sets — can be documented and re-ordered line by line, which matters when a commercial user replaces consumed bits rather than whole cases.

YJTS-3018, 77-piece smartphone repair kit: CR-V6150 bits with a nickel finish, pentalobe, tri-wing, triangle and square profiles, and a durable box for storage and carrying.

Step-by-Step: Specifying a 4V Cordless Tool and Accessory Package

1. Define the fastener profiles by application. Electronics and phone repair work needs pentalobe, tri-wing, triangle and precision Torx sizes. Furniture and general assembly work needs Phillips, Pozidriv, hex and Torx in larger sizes, plus sockets.
2. Set the torque requirement. Decide whether the joint is finished by the motor or by hand. If the required tightening torque exceeds the tool's electric torque — 0.15 N·m, 2.5 N or up to 5 N depending on the model — the package must include a manual tool rated to that value.
3. Confirm the drive interface and the reach. Verify 1/4-inch hex shank compatibility, then add a magnetic bit holder and an extension bar. Reference points in the range are the 1/4-inch × 100 mm magnetic extension bar in YJPS-6851 and the 1/4-inch × 60 mm quick-release extension rod in YJTS-3545.
4. Choose the bit material and length. S2 steel with black phosphate coating for impact-type driving (YJTS-3109, YJTS-3110, which use 1-inch and 2-inch standard bits), CR-V6150 for general driving and hand tools.
5. Add the manual backup in the right format. A folding hex key (YJHK-3075) for portability, a 9-piece ball-point hex key set (105221K2, 71821D2) for offset access at angles up to 25 degrees, or a T-handle wrench (YJHK-3066, YJHK-3226) when the manual torque requirement is high.
6. Size the set from the profile and socket list. The YJTS-3148 29-piece set carries 16 bits plus nine sockets; the YJTS-3506 26-piece set carries 13 bits plus 11 sockets. These two sets serve different jobs despite similar piece counts.
7. Verify documentation and repeat-order data. Record the model number of every component, confirm that certificates are available for the destination market, and keep the set composition list so spare bits and keys can be re-ordered separately.

Use Cases: Where This Specification Pays Off

Electronics and smartphone repair

Precision work needs low electric torque and dense bit coverage. The YJPS-906 electric precision repair tools set delivers 0.15 N·m of electric torque, 3 N·m of manual torque and 0–220 rpm from a 320 mAh battery, with LED lighting and a range of bit types; the YJPS-907 26-piece cordless precision power screwdriver set uses the same 3.7V, 320 mAh platform with a one-hour charge time and 220 r/min. For housing profiles, the YJTS-3018 77-piece kit covers pentalobe 0.8–2.0 mm, tri-wing Y000–Y1 and triangle TA20–TA30.

Furniture assembly

Furniture assembly combines medium driving torque with a wide socket requirement. The YJPS-912 power screwdriver set provides 2.5 N of electric torque and 10 N·m of manual torque at 0–250 rpm from an 800 mAh battery, with LED illumination and a no-load operating time of 50 minutes or more. Pairing it with the YJTS-3506 set (sockets from 4 mm to 14 mm) or the YJTS-3136 set (25 bits plus sockets from 5.0 to 12 mm) covers the typical cam-lock and hex-bolt fittings encountered in flat-pack furniture.

Craft projects and light workshop tasks

Craft work benefits from a compact, rechargeable package rather than a large platform. The YJTS-3526 41-piece household electrical screwdriver tool set runs on a 3.7V lithium battery with 320 mAh capacity, and the YJGG-001 cordless hot-glue pen operates at 150 °C with a glue release time of 30 seconds and an operating time of 120 minutes or more from a 320 mAh battery, charged through a 5 V USB Type-C compatible output.

Light fastening and upholstery

Fastening tools require a different accessory logic. The YJSG-500 two-use lithium electric nail gun and the YJSG-501 five-use lithium electric nail gun both use 3.7V, 2000 mAh batteries rated at 25 W, and are specified by the staples or nails they accept rather than by bits. In a mixed 4V package, buy the consumable format first and the tool second.

Field service and confined access

For service calls, the manual backup is often the tool of first use rather than a fallback. The YJHK-3075 8-piece locking folding hex key set (metric) covers metric sizes in a folding format with heat-treated CR-V6150, and the YJHK-3066 7-piece T-handle set provides chamfered tips and a T-handle designed for greater torque.

YJHK-3075, 8-piece locking folding hex key set (metric): heat-treated CR-V6150, HRC 52–55, folding format for tool bags and confined access.

Comparison Table: Accessory Categories and What Each One Verifies

FAQ

Conclusion: Specify the Package, Not Just the Tool

The 4V cordless tool category works differently from larger cordless platforms. Electric torque is deliberately modest — 0.15 N·m to 5 N·m across the models covered here — because the tool is designed for light, precise, repetitive work. That design choice makes the accessory package part of the tool's specification rather than an attachment to it.

A specification that holds up in use answers six questions: Does the tool take 1/4-inch hex-shank bits, and is a magnetic holder and extension supplied? Are the electric and manual torque figures both documented? Is the bit and hex key steel specified as CR-V6150 or S2, with hardness and surface treatment stated? Is a hex key, folding hex key or T-handle wrench included, and is it rated to the manual torque required? Does the set cover the profile families and socket range the job uses, rather than only a large piece count? And is the set organized and documented so individual pieces can be re-ordered?

Buyers who apply these six checks when comparing 4V cordless tool suppliers will find that reliable packages look similar on paper in the first line of the description and very different in the accessory list beneath it.

Next Step: Request a Sample, Quote or the Product Catalog

HOTAK PRO TOOLS supplies 3.7V/4V cordless tools with matching bits, hex keys, folding hex keys, T-handle wrenches and tool sets, and supports ODM/OEM customization for distributors, importers and private-label programs. Send the model, bit mix and case requirement, and a sample or quotation can be prepared against it.

Email: yjtcl@yj-tools.com  |  Tel / WhatsApp: +86 133-9661-6513
Website: www.yj-tools.com
Address: NO.1 Zhongxin Road, Jiangshan Town, Ningbo City, Zhejiang Province, China

Download the full 2025 YONGJIA catalog (PDF): 2025 YONGJIA CATALOG

In-house production capability behind HOTAK PRO TOOLS: integrated mold development, forging and stamping, heat treatment, surface finishing, precision machining, assembly and packaging in Ningbo, Zhejiang Province.

About the manufacturer: Ningbo (Yinzhou) Yongjia Electrical Tools Co., Ltd. was founded in 2000 and is headquartered in Ningbo, Zhejiang Province, China. It operates a 45,000 m² production base with an annual output of 18,000,000 units, a 25-engineer R&D team and an export ratio of approximately 95% across the EU, USA, Southeast Asia and South America. The company holds ISO9001 certification, TÜV/GS, BSCI and VPA approval, has passed Walmart (USA) and Kingfisher (UK) factory audits, and was recognized as a National High-Tech Enterprise in 2014.