EPA regulations require that whenever a refrigerant retrofit is performed (recharging or converting a refrigeration / AC / Heat Pump system to use a substitute refrigerant), the system must be properly marked. This decal is to be filled out by the servicing technician and affixed on the inside of a service panel or other interior location protected from exposure to rain or sunlight. When used in combination with exterior refrigerant labeling stickers (see our other listings for R-438A and R-407C decals) this leaves a quickly identifiable record for the next technician so they will know what alterations have been made and what they are working on. For a bulk purchase / large quantity wholesale discount please message us. Decal designs are Copyright 2023 RefrigerantStickers.com