Robinair 18480 R134A Oil Injector Includes low side manual quick coupler to connect to the vehicle's A/C system Use this syringe-type injector to add PAG type lubricant oil to a fully pressurized A/C system Just fill the barrel with the amount of oil needed, connect the injector, and press the plunger These self-contained injectors let you add PAG oil to fully pressurized A/C systems (like the ROB48920T) in just seconds R-134a injector has a quick coupler