SUPCO® BULLET® PIERCING VALVE 1/4″, 5/16″, 3/8″ THIS BULLET PIERCING VALVE (SMALL SIZE) UTILIZES THE SAME TYPE OF GASKET FOUND UNDER THE HEAD PLATE OF MOST AIR CONDITIONING COMPRESSORS. WHEN INSTALLED, THE GASKET ACTUALLY COMPRESSES THE COPPER TUBING .020″ CREATING A PERMANENT, LEAKPROOF SEAL THAT WILL WITHSTAND ANY PRESSURE AND TEMPERATURE FOR THE LIFE OF THE UNIT.