Clamping tools use different rings than crimping tools even though both types of tools use HydroPEX (or crimp-style) fittings. All clamping tools use stainless steel rings with a small tab jutting out the side. The jaws of your clamping tool are placed over the tab and the handles of the tool are squeezed together to secure the fitting. With a crimping tool, the rings used are circular and made of copper. The crimping tool's jaws are placed around the entirety of the copper ring and the handles get squeezed together to secure the fitting.
To recap- for clamping tools, use stainless steel clamps and for crimping tools, use copper crimp rings.
PEX Clamp Tools and PEX Crimp Tools can be found at www.supplyhouse.com
