1. Stud extractor tool uses 3/8 inch-drive, best used with impact wrench and ratchet. Also compatible with with flat wrenches, adjustable wrenches, sockets, and locking pliers. 2. This extractor tool is adjustable to fit studs that are 1/4-inch to 1/2-inch (6mm to 12mm). Manufactured with a Chrome Vanadium Body with Chrome Molybdenum Jaws and will remove broken and damaged threaded studs fast. 3. This extractor tool is easy to operate and can help you rest time, whether it is the exhaust manifold, fuel plug, broken bolts, or broken, painted, rusted fastening screws The posts are effectively removed, but the threaded surface may be slightly worn due to the strong clamping force. Operational guidance: Place the stud extractor on the stud and turn the bottom hex flat nut counterclockwise to tighten the jaws. After the jaws hold the broken bolt or stud firmly, continue to rotate the stud counterclockwise until it is removed.Then release and separate them in a clockwise direction.But the threaded surface may be slightly worn due to the strong clamping force. Specifications: Color: silver Scope of application: 6-13mm Material: Metal Package Contents: 1 x stud remover Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.