Watts LFA109 Compression Union, 3/8-Inch OD x 1/4-Inch OD This compression fitting is easy to use for both contractors and the do-it-yourselfer Unique Ander-Lign compression fitting is the only fitting that is completely assembled with a captive sleeve The bodies are interchangeable with standard compression For use with copper, brass, aluminum, and plastic tubing Lead-free brass is not more than a weighted average of 0.25% lead when used with respect to the wetted surfaces of pipes and pipe and plumbing fittings and fixtures