socket pressure plugs are manufactured to suit applications where a pressure tight seal is required with no spiral leakage through the thread form. For maximum sealing taper tapped recommended. Precision-forged deep sockets with smooth, flat walls and controlled corner radius to ensure even distribution of driving torque Threads are precision rolled to provide smooth fully formed tapered threads for a high pressure seal. Rolled threads improve the sealing action by eliminating spiral machining marks. Controlled structural grain flow and greater wall thickness provide superior bursting resistance.