Royal Purple fluids are proven to make equipment run smoother, cooler, quieter, and longer. Synfilm Recip. 100 is recommended to lubricate reciprocating piston-type air compressors. It is a high-film strength synthetic lubricant that greatly increases the reliability and longevity of reciprocating air and shop compressors. Formulated with Royal Purple's proprietary Synerlec additive, Synfilm Recip. 100 forms a better seal to reduce friction between the cylinder wall and piston rings for greater efficiency. It also minimizes wear and keeps discharge valves free of harmful carbon deposits.