Articco DVP-31 Line Tap Valve, Bullet Piercing Valve These valves are generally installed on round suction lines or uneven tubing on the high side as a " Requires 2" clearance around tubing. For 1/4", 5/16" and 3/8" O.D. tubing Sealing Head Cap Screw and contacts for leak-free Installations Includes Installation Instructions in the package.