Slides over R134a can for quick and easy charging. Comes with adaptor for 4oz. oil charge. Fits any 12oz. R134A refrigerant can. Comes with brass threaded fitting for durability. Easily connects to R134A refrigerant gauge setR134a Side Can Tap design makes servicing A/C systems with 12 oz. cans of R134A refrigerant and 4oz. cans of A/C oil charge faster and easier than ever before.