Mastercool is the leading manufacturer of professional quality A/C manifold gauge sets. Our manifold gauge sets are constructed of the finest materials and machined with precision to the highest quality standards. At Mastercool, every manifold we build is built to last. Anti-flutter gauges smooth out needle movement Easy to read temperature scales on 3 1/2″ gauge face (Bar/PSI/˚F/˚C) Easy grip front-facing knobs Piston type free-floating valves reduce o-ring wear E-Z to recalibrate gauges to insure accuracy Extra large sight glass for visual checks of refrigerant Manifold block assembled with (3) 12mm-F fittings per SAE J2888 Red & Blue Nylon barrier hoses with 12mm-M fittings on both sides meets SAE J2888, EPA, SAE & UL standards Yellow hose 12mm fitting on one side and 1/2 x 16 LH acme on the other meets SAE J2888 R1234yf high and low side couplers with extended disconnect protection sleeve meets SAE J639 & J2888R1234yf 2-Way Piston Valve Manifold Gauge Set includes 3-72″ hoses and R1234yf couplers packaged in a clamshell