Proto J7421M Impact Socket 1/2 in Drive 21mm 6-point

Product Description

The PROTO J7421M is a 21mm, 6-point impact socket designed for 1/2 inch square drive impact wrenches and ratchets. Built for high-torque fastening applications, it features a hex drive style and an overall length of 1-39/64 inches. The 6-point geometry maximizes contact on fastener flats, reducing rounding under heavy load. At 0.3 pounds, it is light enough for repeated overhead or tight-space use without adding tool fatigue. Mechanics, fleet technicians, and industrial maintenance trades rely on this socket for wheel, suspension, and general mechanical fastening work where impact-rated tooling is required.

This socket is suited for automotive, heavy equipment, and industrial maintenance environments. The 21mm size is commonly used on lug nuts, suspension fasteners, and drivetrain components across a wide range of domestic and import vehicles. It is appropriate for both shop and field use wherever a 1/2 inch drive impact tool is in service. The compact overall length keeps it usable in moderately tight access areas without requiring an extension in most standard applications.

Key Features

• 1/2 inch square drive fits standard impact wrenches and ratchets
• 21mm socket size covers common lug nut and fastener applications
• 6-point hex drive design maximizes fastener contact and reduces rounding
• Overall length of 1-39/64 inches suits most direct-drive applications
• Impact-rated construction handles high-torque tool output
• Lightweight at 0.3 pounds for reduced fatigue during extended use

Compatibility

Designed as an OEM-style impact socket for use with any 1/2 inch drive impact wrench, air ratchet, or breaker bar requiring a 21mm, 6-point hex socket.

Installation Notes

Impact sockets should only be used with impact-rated tools. Do not substitute chrome hand-tool sockets on impact drivers, as chrome sockets are not rated for the shock loading of impact tools and can fracture. Ensure the socket is fully seated on the drive anvil before applying torque. Inspect the socket and retaining pin or ring for wear before each use, and replace if cracks, deformation, or excessive wear are present.