A go-no-go gauge checks crimp fittings to ensure that they will not leak. The go-no-go gauge featured on SupplyHouse.com works with copper crimp rings ranging from 3/8” to 1”. Using a go-no-go gauge is easy. Just place the gauge on the ring. If the gauge does not fit around the ring or if it allows the ring to reach the bottom of its slot, the crimp was made improperly. Rings from successful crimp fittings should fit securely in the center of the gauge. Check out our Resource Center for more helpful tips and an instructional video on PEX crimping.