- New
21848 is a LaSalle Bristol plumbing union fitting with a 3/8" male pipe thread (MPT) connection and a 1/4" barb connection. It is designed to provide a transition between a threaded plumbing connection and compatible tubing. This fitting is listed for RV and recreational vehicle plumbing applications. Verify the tubing size, thread type and system requirements before installation to ensure compatibility with the existing plumbing system.