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 Body with Chrome Jaws and remove broken and damaged threaded studs fast. 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. 3. This extractor tool is easy to operate and can help you rest time, whether it is the exhaust manifold, plug, broken bolts, or broken, painted, rusted fastening screws The posts are effectively removed, but the threaded may be slightly worn due to the strong clamping force., Manufacturer: Akfldms