The Swiftech Lok-Seal? Compression Fitting G1/4 Thread - 3/8" ID x 1/2" OD is a compression fitting used for tubing with 3/8" inner diameter and 1/2" outside diameter. Both base and a second swivel located at mid fitting rotate 360? for optimum tubing orientation; the female thread allows installation of a compression fitting to make a 90? Dual Swivel elbow fitting. G?" Male And Female Threads 360? Dual Swivel With Hi-Flow 10.2 mm Bore