10pcs 4mm x 160mm Glass Stone Flat Ring Diamond Needle Files

Process:by plating, so that the emery adsorbed on the substrate (45 steel) surface.  (C45).

Feature:  wear-resistant, surface sand close next, not falling, keep the sharpness, long-term wear-resistant.

Surface finish: matrix part of the nickel plating layer, bright, high-finish, finish by working part sand; granularity to decide the finer sand and finish as possible. 150 mesh and 200 mesh

Details specifications: