Proto J5021MH Deep Hand Socket 21mm 3/8 Drive 6-point

Product Description

The PROTO J5021MH is a deep hand socket designed for professional-grade fastener work in demanding trade environments. Built for a 3/8 inch drive, this 6-point socket fits 21 mm fasteners and delivers a full, flush engagement that reduces rounding on hex heads. The deep-length design accommodates extended bolts, studs, and recessed fasteners that standard-depth sockets cannot reach. A chrome-plated finish provides corrosion resistance and makes the socket easier to wipe clean in shop and field conditions. This socket meets ASME B107.5 standards, confirming dimensional and strength compliance for professional hand-tool use.

The J5021MH is suited for automotive, heavy equipment, plumbing, HVAC, and general mechanical work where a 21 mm deep socket on a 3/8 inch drive is required. Its compact footprint at 1.07 inches wide makes it workable in moderately tight spaces, while the 2.75 inch length gives clearance over protruding studs and long bolt shafts. Mechanics, service technicians, and trade professionals reaching for a reliable deep socket for daily use will find this a straightforward, standards-compliant tool.

Key Features

• 21 mm socket size for metric fastener applications
• 3/8 inch drive compatibility for standard ratchets and extensions
• 6-point contact geometry reduces fastener rounding versus 12-point design
• Deep-length body clears extended bolts, studs, and recessed hex heads
• Chrome-plated finish resists corrosion and simplifies cleaning
• Meets ASME B107.5 standards for hand socket dimensions and performance

Compatibility

Designed as an OEM-style replacement or direct addition to any 3/8 inch drive hand-tool set requiring a 21 mm deep 6-point socket.

Installation Notes

Install and remove with any standard 3/8 inch drive ratchet, breaker bar, or torque wrench. Ensure the socket is fully seated on the fastener before applying torque to avoid slippage. Inspect the socket for cracks or deformation before each use and remove it from service if any damage is found. Do not use impact drivers with this hand socket unless the tool is explicitly rated for impact use.