for testing raised and lowered curves, standard steel, concave and convex gauge blades, finely cut radius shapes, number of blades 17, gradient: from 1-3 mm each 0.25 mm, then 0.5 mm, number of blades 16, gradient: each 0.5 mm, number of blades 15, Pitch: from 15.5-20 mm each 0.5 mm then 1 mm