Internal Pipe Wrenches are designed to easily remove broken pipe threads, plugs and fittings. Multiple uses including broken heater hose fittings, household plumbing, to HVAC connections. Machined heat-treated cams mounted on alloy steel hex shafts. Use with a standard socket and ratchet or your open-box end wrench. Set includes 3/8 inch, 1/2 inch, and 3/4 inch extractors.