Inhouse product
These service/access valves are usually brass or copper with a built‑in Schrader fitting (similar to a tire valve core) that lets you connect manifold gauges, charge hoses, or service tools.
Many kits also include core removal tools so you can extract or install the core without releasing refrigerant during service.
They are used for:
Charging refrigerant into HVAC systems (R22, R12, R134a, R410A, etc.)
Pressure testing and vacuum checks
Replacing Schrader cores without depressurizing system