1Excellent Aluminum Material: This AC oil dye injector is made of excellent aluminum material, which is sturdy and wear resistant, not easy to be damaged, and has a long service life. 2Wide Application: This AC oil dye injector has a wide range of applications and can be used for fluorescent dyes for leak monitoring, all oil types (POE or mineral oil) as well as all home office ac and automotive ac systems. 3R134A Low Side Quick Connector: This AC oil dye injector features an R134A low side quick connector with a 1/4 inch SAE male and 13mm female. 4Easy Operation: With a refrigeration AC oil dye injector full of refrigeration oil, screw the check valve onto the cartridge and tighten. Tighten the inner and outer cylinders clockwise, then use a bit of 1/4 SAE threaded insert to expel a small amount of air from the blue tube. Connect the low pressure port of the refrigeration system to be refueled and add the required amount of cooling oil to the inner and outer cylinders. 5Main Function: This AC oil dye injector has a capacity of 1/4 oz to 2 oz and is used to inject oil and dye into the air conditioning compressor through the low pressure suction side.