The C&D Valve B10-743 (also known as CD2250) is a brass wrench cap designed for use in refrigeration, HVAC, and air conditioning systems. It fits standard 1/4" SAE flare valves and provides a reliable seal while allowing easy valve access for maintenance and pressure testing.

The wrench cap features a built-in core wrench tool on the top, which makes it convenient to remove or tighten the Schrader valve core without requiring a separate tool. It also has a neoprene O-ring that provides an effective seal to prevent refrigerant leaks and contamination.

These caps are commonly used by HVAC technicians and contractors during installation, service, and repair work to protect valves and maintain system integrity.