Curved tooth files are made from alloy steel and have teeth which are undercut resulting in faster cutting with less effort. They may be used on all materials from aluminium to hardest steel without clogging. The undercut and generous radius at the root of the teeth enables the file to clear itself whilst in use. The blade type files are without a tang and have a hole at each end for attachment to a holder. Dreadnought files feature a curved tooth across the blade. Length: 350mm (14in).9 Teeth per inch.