Williams Comfort Products JHWISFX420 Flextension 3/8 in Drive

Product Description

The WILLIAMS COMFORT PRODUCTS JHWISFX420 is a Flextension — an integrated drive extension and socket combination engineered for demanding industrial fastening applications. The 3/8 inch drive unit accepts a 5/8 inch, 6-point socket that is permanently fixed to the extension body, eliminating the risk of socket separation during continuous operation. A TIG-welded retention pin transfers full rotational power directly to the socket. The SUPERTORQUE lobular socket opening grips fastener flats rather than corners, reducing deformation under load. Maximum working torque is rated at 160 ft-lbs (1,920 in-lbs / 217 Nm). The drive end features a 7/32 inch cross-hole bevel for easier engagement. This tool is suited for licensed mechanics and assembly technicians working in high-cycle production or heavy equipment service environments.

The JHWISFX420 Flextension is used extensively in engine manufacturing, heavy equipment assembly, and mechanical repair operations where a standard extension-and-socket combination risks disengaging mid-task. The integrated design supports reliable, uninterrupted work cycles on both hand tools and power tools including impulse and direct-drive tools. The tool allows up to 30 degrees of angle offset, giving technicians access to fasteners in confined or angled locations. This unit is NOT rated for impact tool use and must not be used with impact drivers or impact wrenches.

Key Features

• Integrated non-removable socket and extension body — socket cannot separate during use
• TIG-welded retention pin provides full rotational torque transfer
• SUPERTORQUE lobular 6-point opening reduces fastener deformation under high torque
• Up to 30 degrees of angle offset for access in confined spaces
• 7/32 inch cross-hole bevel on drive end for easier tool engagement
• Black Oxide finish for corrosion resistance and reduced glare
• Made in the U.S.A.

Compatibility

Designed for use with 3/8 inch drive hand tools and power tools (impulse or direct drive). Not compatible with impact tools. Other lengths and socket sizes are available by special order through Snap-on Industrial Brands representatives.

Installation Notes

This Flextension is intended for installation by qualified mechanics and industrial assembly technicians. Before use, confirm the tool is connected to a compatible 3/8 inch drive hand tool or direct-drive power tool — never connect to an impact wrench or impact driver. Do not exceed the maximum working torque rating of 160 ft-lbs. Inspect the TIG-welded retention pin and socket opening for wear or damage before each use and remove the tool from service if deformation is observed.

Technical Specifications

• Drive Size: 3/8 inch
• Socket Size: 5/8 inch
• Socket Type: 6-Point
• Maximum Working Torque: 160 ft-lbs / 1,920 in-lbs / 217 Nm
• Angle Offset: Up to 30 degrees
• Drive End Cross-Hole Bevel: 7/32 inch
• Finish: Black Oxide
• Weight: 0.4 pounds
• Country of Origin: USA

Standard Information

• Brand: WILLIAMS COMFORT PRODUCTS
• Manufacturer Part Number: JHWISFX420