Proto J4990-8MST Hand Hex Bit Socket 3/8 in Drive 8mm

Product Description

The PROTO J4990-8MST is a hand hex bit socket designed for manual torque applications where a standard hex drive is required. Built around a 3/8 inch square drive, this socket accepts an 8 mm hex bit and delivers a compact overall length of 1-49/64 inches with a 3/4 inch bit engagement length. It is the kind of straightforward, no-nonsense socket that belongs in a service technician's drive set for equipment access, fastener removal, and assembly tasks across HVAC, plumbing, electrical, and general mechanical work.

This hex bit socket is suited for residential and light commercial service scenarios where an 8 mm hex fastener is present and access depth is limited. The 3/8 inch drive size makes it compatible with the mid-range ratchets and torque wrenches already common in most trade toolkits. Typical applications include panel fasteners, valve body bolts, equipment mounting hardware, and similar hex-drive fasteners encountered during routine service calls.

Key Features

• 3/8 inch square drive for use with standard mid-range ratchets and torque wrenches
• 8 mm hex bit size for common metric hex fasteners
• Compact overall length of 1-49/64 inches suits confined access areas
• 3/4 inch bit length provides positive engagement on fastener heads
• Single-piece hand socket format for direct manual or ratchet use

Compatibility

Designed as a standard 3/8 inch drive hex bit socket for use with any 3/8 inch drive ratchet, extension, or torque wrench accepting conventional square-drive tooling.

Installation Notes

Ensure the drive tool and socket are fully seated before applying torque to avoid rounding the fastener or damaging the drive. Disconnect power or shut off the relevant system before accessing fasteners on electrical enclosures, mechanical equipment panels, or pressurized assemblies. Hand tools of this type do not require special licensing but should be used within the rated drive size to prevent tool failure.