Nylon Liquid Tight Threaded Plugs Heyco Nylon Liquid Tight Threaded Plugs provide an integral sealing ring to ensure a superior seal at the mounting hole location, every time. The IP68 plugs provide a liquid-tight seal up to 70psi and are UL rated for type NEMA 3R, 4 and 4X applications. They have a hex-shaped head with a slot for wrench or screwdriver installation and are made from electrically non-conductive Nylon 6/6. This non-corrosive material resists salt water, weak acids, gasoline, alcohol, oil, grease, and common solvents. Heyco Nylon Liquid Tight Threaded Plugs are a cost-effective option over brass or steel NPT and PG plugs. These threaded plugs are ideal for hydraulic and pneumatic applications.