This 1/4 in quick connect straight valve works with copper, CPVC, LPDE, PEX, MPDE, HDPE and polybutylene tubing's. Easy to install, no tools or tube inserts required and the fittings can be used for hot and cold water applications. The unique O-ring guide feature insures zero-leak connections. Unlike barb fittings, it joins the tubing on the outside, increasing the flow capacity. After a connection has been made, even under maximum pressure, the tubing is able to swivel making the quick connect fitting ideal for vibrating and dynamic applications.