Supco Tradefox Nitrogen Purge Boot Part Number TFXNPB Designed to assist the technician in the purging and brazing process. O-rings fit and seal over various sizes of ACR tubing creating a "hands-free" and hassle-free solution between your nitrogen regulator and the refrigerant line. Features/Specifications: Works on 3/8", 1/2", 5/8", 3/4", 7/8", and 1-1/8" OD ACR O-rings are compatible with all refrigerants, oils, and flushing agents Used on refrigeration tubing only Tubing must be de-burred prior to use Do not install on oval or kinked tubing Do not pressurize above 20 psig Use only with nitrogen, do not use with flush O-rings are not replaceable Always wear eye protection and gloves when using this product Hands-free way to purge Fits over copper line sets