This SNGN solid CBN insert,are mainly for roughing and finishing machining cast iron alloys and hardened steels, like cast iron alloy brake discs,brake drum, engine block and so on. We developed different CBN grades upon customers different use.our suitable CBN grade could insure the good surface finish and longer cutting life. The popular size are: SNGN090408,SNGN120416,SNGN120712,SNGN201024.