RED TEK ProSeal22 A/C Seal Treatment (4 oz. can) Operation: Easy to use. Installs in minutes. Remains in system as a liquid lubricant ready to seal any future leaks. Lower Cost: Less expensive than replacing leaking evaporators, condensers, compressors, and metal lines. Compatibility: Compatible with most common refrigeration materials and lubricants including R22, metal components, mineral and synthetic(Ester and PAG) lubricants, seals, gaskets, hoses, compressors, and o-rings. Environment: Helps environment by reducing refrigerant emissions. Safety: Safe and easy to use. Less toxic than other seal treatments that contain poisonous methanol. No long term health risks have been attributed to RED TEK ProSeal.