No. 3 Finish contains short, relatively coarse, parallel polishing lines. These lines extend uniformly along the length of the coil. No. 3 can polished mechanically with gradually finer abrasives or by passing the coil through special rolls, which create a pattern into the surface that replicates the appearance of mechanical abrasion. No 3 Finish is moderately reflective. The surface roughness is usually less than Ra 40 micro-inches. When mechanically polishing, the steel is initially polished with 50 or 80 grit abrasives, and the final finish is typically uses 100 or 120 grit abrasives.