This Faithful Round Second Cut Engineers File is ideal for filing circular openings or concave surfaces and slightly tapered towards the point, with a double cut finish. For professional and frequent DIY use, fitted with a comfortable handle. Second Cut: Approx 36 teeth per 25mm (Medium). The FAIFIRSC6 Engineers' File has the following specifications: Cut: Round Second. Blade Length: 150mm (6in). Blade Width: 6mm (1/4in). FAIFIRSC6