... Gas,Water, Oil. Copper Coil for Air-Conditioner, Refrigeration, Natural Gas,Water, Oil.Copper Coil: Copper LWC Coil, Inner-Grooved Copper LWC Coil.Outside Diameter is as following:1. Copper LWC Coil: 4mm ... -22.23mm2. Inner-Grooved Copper LWC Coil: 5mm ...