Compresses stainless steel clamp rings to secure PEX or PE-RT tubing to brass or poly crimp fittings. The 3-handle design version allows for one-handed gripping keeping the other hand free to hold a flashlight, ladder or pipe. One tool works with all size clamps from 3/8 In. to 1 In. When properly calibrated, this tool eliminates the need to check each fitting ring with a Go / No-Go gauge.