Williams HKT-4MM 4.0mm Hex T-key 6 Inch Arm

Product Description

The WILLIAMS HKT-4MM is a 4.0mm hex T-key with a 6-inch arm, designed for driving and loosening hex socket fasteners in tight or high-torque applications. The T-handle configuration provides a firm, two-handed grip for increased torque compared to standard L-shaped hex keys. This tool is suited for mechanical assembly, equipment maintenance, and service work across HVAC, plumbing, and general trade applications. Manufactured in the United States, the HKT-4MM is a single-piece hand tool sold individually and is part of the Williams professional hand tool line.

The HKT-4MM is used wherever 4.0mm hex socket fasteners are present, including equipment panels, valve assemblies, motor mounts, and machinery covers. The 6-inch arm length extends reach into recessed fastener locations. It is appropriate for both bench work and in-the-field service calls where a standard L-key lacks the leverage or reach needed. Trade technicians across HVAC, refrigeration, plumbing, and electrical disciplines commonly carry T-key sets for routine equipment service.

Key Features

• 4.0mm hex drive size fits metric hex socket fasteners
• 6-inch arm length provides extended reach into recessed fastener locations
• T-handle design delivers increased torque over standard L-shaped hex keys
• Manufactured in the United States
• Sold individually as a single unit

Compatibility

Designed for use with 4.0mm hex socket cap screws and set screws in metric fastener applications across general mechanical, HVAC, plumbing, and electrical equipment service.

Installation Notes

No power source or shutoff is required for hand tool use. Ensure the hex key seats fully into the fastener socket before applying torque to avoid rounding the socket. Inspect the tool for wear or deformation before each use. Follow equipment manufacturer service procedures and applicable codes when servicing any mechanical or trade system.