High Quality Materials: QWORK Metal Nut Splitter Biscuit is made of high quality bearing steel, with high hardness, clean cutting, anti-rust and anti-corrosion. Specifications: 9-12mm / 12-16mm / 16-22mm. Easy to use: turn the nut separator bolt to act on the target nut. Applicable to: Used to remove damaged or corroded nuts without damaging bolt threads. Application: Very suitable for DIY use by mechanics and steelworkers. Use with sockets/spanners/spanners etc.