Nuts and Nipples with filter, replacements for gas regulators - Precisely machined on high-quality brassRegulator side thread: 1/4" NPT - Length: 3.5"Available for the following Gas regulators: CGA-540: Oxygen, CGA-300: Acetylene and Ethyl Cloride, CGA-580: Nitrogen, Argon and Helium, CGA-510 Acetylene and Propane, CGA-346: Air, CGA-326: Nitrous Oxide, CGA-320: Carbon Dioxide, CGA-350: Hidrogen - Choose the one you need from the Style menu options.***READ THIS BEFORE YOU BUY*** Carefully measure the connectors on your regulator and tank valve and check the drawings with the dimensions and description on Picture #2. Make sure they will fit.***READ THIS BEFORE YOU BUY*** Carefully check your regulator and the gas cylinder´s valve and look for their CGA number and gas use. Never replace parts of a regulator with parts intended for a different gas.