2128 A/C Flush Solvent, 4 x 1-Gallon: Developed specifically for use in air conditioning systems using refrigerants R12 ,R134a, and Blends. Compatible with Mineral, Ester, Paraffin, and PAG oil. Removes moisture, acid, and contaminants that can block the flow of oil and refrigerants, resulting in system failure. Prevents acid from forming and neutralizes any acid presently in the system.