PRACTICAL SET:The retrofit valve include R12 to R134A retrofit conversion adapter with dust cap,BPV31 bullet piercing tap valve, a hex key, 2 adapters HIGH QUALITY:The retrofit valve is made of zinc alloy and the R134 Piercing Tap Valve is made of high quality brass alloy for durable and long-lasting to use FUNCTION:Universal retrofit valve with 7/16" low side port, automotive air conditioning refrigerant systems converting from R12, R22, R502 to R-134A. BPV-31 bullet piercing tap valve fits for 1/4", 5/16", 3/8" outside diameter pipes. Replace part No. AP4502525, BPV31D, GPV14, GPV31, GPV38, GPV56, MPV31 EASY TO USE:Bullet piercing tap valve: just screw it on then it's okay; BPV-31 bullet piercing tap valve: you only need 1 hex key wrench (included) to install this part ATTENTION!!!!:Before you click add to cart, please check to see that it is "Sold by KYMY" and "Fulfilled by Amazon". Our products stocked in the Amazon warehouse, Amazon will be packing and shipping it with Amazon logo on the package. Generally, the transportation time by Amazon will not exceed 7 days, please check with shipping terms. 24 hours service, 30 days refund without any reason