The valve is used for air conditioning with R22,R407C,R410a refrigerant, to connect indoor unit and outdoor unit. Through operating valve stem, the inner circle can be closed. It can be a checking valve to drain air and add refrigerant during maintaining, also be used in other refrigerant circle systems. Including flare nut and dual tube types, connection dimension from 5/8" to 1-1/16". Refrigerant: R22, R40C7, R410a Fluid temperature: -20~+120