Enzotech Compression Fittings for 1/2" x 3/4" Tubing (Set of 2 Fittings) Set of 2 Fittings with Nickel Finish G1/4" Threads with O-ring For tubing with a 1/2" Inner Diameter and 3/4" Outer Diameter High Quality Construction *Be sure to screw the collar of the fitting down tightly to make certain that your tubing does not come loose*