Texas Pneumatic Tools square head plugs attach at the ends of pipes, shafts, tubes or connectors and provide safety in high-pressure air, water and natural gas systems. These threaded square plugs are made of high-quality metal for a steady performance and high thermal resistance. They further feature a galvanised zinc plating for rust protection and a simple design that requires little maintenance. Raptor Supplies offers an array of these hydraulic plugs in 1/4, 3/4, 3/8 and 1 inch sizes.