Enviro-Safe R-290 Refrigerants with Top Tap #9935 Description This is the same top tap as the #5000 but we have added a fitting to the tap. This allows a standard 1/4" 20 flare hose (R12, R22, R502) to be used with this tap. Enviro-Safe no longer markets or sells Enviro-Safe 22a or Enviro-Safe 502a for use in the USA. Enviro-Safe is marketing an EPA-approved refrigerant (R-290 CAS #74-98-6) for use in new food refrigerators and freezers (stand-alone units only), and some industrial applications, in accordance with EPA regulations at 40 CFR Part 82.17. It is sold in 8 ounce cans and 30lb 50lb cylinders! The temperature pressure chart represents the temperature of the product when inside the system. Here are some guidelines for charging with R-290 (description exceeds maximum possible length)