After recovering refrigerant and performing component service/replacement in an A/C system, any oil lost during the recovery process must be replenished. GM-50745 is used to inject oil into R1234YF A/C systems that use POE oil. It is critical that POE oil used in electric compressor systems and PAG oil not be intermixed, so specific oil injection hoses for PAG and POE are required. Individual injection hoses help assure that no POE oil system becomes contaminated with PAG oil. A large, durable tag wrapped around the GM-50745 hose clearly denotes it is only for R1234YF POE oil A/C systems. Use with GM-45037 A/C Oil Injection Kit. For R1234YF PAG oil systems, use the GM-50744 Oil Injection Hose.