Designed for repair use, for air condition, refrigeration and other equipments needing repair and fixing; for opening and closing compressor service valves, rotalock val ves and shutoff val ves Bit Adapter: 2 inch long, size: 3 / 16 ' ' and 5 / 16 Hvac service wrench set are metal, strong, and resistant the bit adapter is heat-treated black coating There are 3 types you can choose, 1 set curved ratchet wrench, 1 set straight ratchet wrench and 1 Hexagon Bit Adapter 4 Different Sizes of Refrigeration Service Wrench Set: 1 / 4 ", 3 / 8 ", 3 / 16 ", 5 / 16 ", these sizes are the most commonly used sizes when repairing the air conditonning and refrigeration equipment, Manufacturer: Yhplxyuus