steel files,files set,hand tools,files. Packing: 5pcs / set steel file:φ3mm*140mm*50mm granularity:100-120#Electrodeposit process is used to electroplate diamond on base, which is applied to hard materials such as hard steel, ceramics and glass. The standard shapes are flat, round, semicircle, square, triangle, sharp-flat, knife-shaped, single-sided triangle and oval.