Flange adapter fittings are commonly used for hydraulic applications on mobile equipment. These flange adapters are installed using four bolt flange kits and heavy duty bolts. The flat face has a machined O-ring groove to accept an O-ring (of either Buna N or Viton material). Code 61 flange adapters are rated to 3000 psi while Code 62 flange adapters are rated to 6000 psi. These adapters are equivalent to parts from Caterpillar hydraulics, Parker, Gates, Goodyear, and Eaton Aeroquip.