Proto J7021M Impact Socket 3/8 in Drive 21mm 6-point

Product Description

The PROTO J7021M is a 21mm, 6-point impact socket designed for 3/8 inch drive impact wrenches and ratchets. Built for heavy-duty fastening applications, this socket delivers the torque transfer and wall thickness required to handle impact tool loads without cracking or rounding fasteners. The hex drive style and 6-point geometry provide maximum contact on hex fasteners, reducing the chance of slippage under high-torque conditions. With an overall length of 2-47/64 inches, it fits in moderately tight access areas. Mechanics, automotive technicians, and maintenance professionals rely on this type of socket for wheel service, suspension work, and general assembly tasks.

This socket is suited for automotive, light truck, and general industrial applications where a 3/8 inch drive impact tool is used. The 21mm size is a common metric fastener size found throughout European and Asian vehicle platforms, as well as modern domestic vehicles. It is appropriate for both shop and field use, particularly in scenarios involving wheel lug nuts, chassis hardware, and drivetrain components where consistent torque application is critical.

Key Features

• 3/8 inch drive fits standard 3/8 inch impact wrenches and ratchets
• 21mm socket size covers a widely used metric fastener dimension
• 6-point hex geometry maximizes contact area and reduces fastener rounding
• Overall length of 2-47/64 inches suits moderate-depth fastener access
• Impact-rated construction handles repeated high-torque cycles

Compatibility

Designed as an OEM-style replacement impact socket for use with standard 3/8 inch drive impact wrenches, air ratchets, and hand ratchets requiring a 21mm, 6-point metric socket.

Installation Notes

Install and remove this socket by hand before applying impact tool power to confirm proper seating on the fastener. Ensure the drive detent or retaining ring is fully engaged on the impact tool anvil before use. Inspect the socket for cracks or deformation before each use and remove from service if damage is found. Impact sockets are not rated for use with torque multipliers or breaker bars unless the manufacturer specifies otherwise.