McElroy Test Caps are designed for quick and easy air pressure testing of polyethylene pipe. All of our test caps are reusable, provide a positive o-ring seal and have been pressure rated to 165 PSI to meet 49 CFR192.513. Installation and removal is quick and easy on pipe sizes from ½" CTS to 2" IPS. Test pressure actually improves the cap's grip on the pipe. One test cap is required per pipe size. They are made of corrosion-resistant material and are durable in construction.