Robinair (60072 Enviro-Guard Hose Set for R-134a - 72", Set of 3 Enviro-Guard automotive A/C service hoses feature a special barrier material that prevents virtually any permeation of refrigerant yet still remains flexible 72 inch long, 1/4 inch yellow, blue, and red hoses are clearly marked for R-134a and feature a 500 PSI working pressure and 2500 PSI burst pressure Brass 1/2 inch ACME female fittings on both ends (yellow hose) and 14 mm male x 1/2 inch ACME female fittings (blue and red hoses) Coupler nuts feature deep knurling for a positive grip that enables quick finger-tightening Hose ends feature a strong six-sided crimp that provides a secure, reliable connection between the hose and barb - even at maximum pressure