Choose a PEX crimp tool that allows you to spend more time working and less time making adjustments. Designed to compress copper crimp rings to secure PEX or PE-RT tubing to brass or poly crimp fittings. Compress the PEX tool over crimp rings at a 90 angle until handles are closed and the go test fits snuggly over fitting while no go does not fit at all (using provided Go / No-Go Gauge). When using with stainless steel clamp rings, the PEX crimp tool will not release until the clamp is fully closed.