The FJC R-1234yf Conversion Kit with Manual Couplers, No. 6820, can be used to convert R-12 or R-134a manifold gauge sets to connect to R-1234yf mobile A/C systems. Features a brass high-side manual coupler with M12 fitting and a brass low-side manual coupler with M12 fitting. In addition there are two fittings (M12 by 1/4" SAE) to connect high- and low-side manual couplers to 1/4" R-12 hoses; and two fittings (M12 by M14) to connect the high- and low-side manual couplers to M14 R-134a hoses.