The EZ Chill A/C Recharge Reusable R-134a Gauge and Hose features a diagnostic gauge easy-to-use trigger dispenser and ninety degree coupler. The gauge is able to diagnose if a recharge is needed identify the current low-side pressure in the system and determine increases in pressure during the recharge process. This product is designed for EPA compliance and to work only with R-134a cans with self-sealing valve can tops. This item contains R-134a.