Auto Fluorescent Leak Detection Auto Air Conditioning R134a Refrigerant Gas Freon AC Leak Test Detector Repair Tool UV Dye Dear customer, please attention: Because batteries are contraband, we will take them out before sending. If you need to buy fluorescent oil, please select ciaoniao special line when submitting the order. Thank you!!! Description This is automotive air conditioning ac system leak tester detector. It is a very effective way to detect leaks in any oil-based system. Compatible with all refrigerants (R22/R134a/R410a/R502/R12/R403/R404/R407 etc) How to use? Putting this additive into air conditioning system pipeline by an injector thru compressor low pressure side (We have injector for sale). Then run the air conditioning system for about 10 minutes. Then find the leak by uv flashlight.