The Hydraulax Hydraulax 1" NPTF Pipe Cap 5406C-16 is designed for dependable hydraulic connections. Part Number: 5406C-16. It is Protects hydraulic systems from debris, Threaded for easy install and removal, Keeps dirt, debris, and fluids from entering open ports, Ideal for field service or system maintenance, and Perfect for protecting unused or service-line fittings.