Refrigeration Ratchet Wrench 4 Sizes. 3/16" 1/4" 1/2 & 9/16" CT-123 Port Valve HVAC/Refrigeration Tool Straight, Heavy Duty, for open/close square and hex Service Valves Four Sized: 1/4" and 3/16" Square and 9/16" and 1/2" Hex Ratchet. Flip to reverse. Specially designed for use HVAC access valves in hard to reach places