The Robinair 68336A 36" Red Enviro-Guard hoses for automotive R-134a meet all specifications for low permeation construction. Clearly marked for R-134a, they have 740 psi working pressure; 3700 psi burst pressure. Robinair premium refrigerant charging hoses are built for long life and dependability. A strong, six-sided crimp provides a reliable connection between the hose and barb, even at maximum pressure. The coupler nuts are deeply knurled for quick finger-tightening. Enviro-Guard hoses are ideal for high pressure applications, including R-410a systems. In-line ball valves control refrigerant flow, open and close in a quarter turn. Special barrier material prevents virtually any permeation of refrigerant, yet remains flexible. The 45° Quick Seal fittings prevent any refrigerant loss when disconnecting hoses from fittings, eliminating harmfull refrigerant burns.