Nu-Calgon s A/C ReStart is a specially formulated POE lubricant based product designed to aid in oil migration of existing oil when replacing the R-22 refrigerant with R-407C, R-427A or others in air conditioning/heat pump systems. A/C ReStart also includes Rx-Acid Scavenger technology to address acids at retrofit. The four fluid ounce bottle is to be used with the reusable A/C Re-New Injector Tool (4057-99). A/C ReStart Connect Inject is a quick, one-time disposable injector option for introducing the treatment into the air conditioning system with the use of the reusable Connect Injector Tool (4155-01).