High performance grain blend in a proprietary bond Extremely fast metal removal – 50% more than straight aluminum oxide 20% less heat generation than aluminum oxide Virtually iron free – contains only .035% iron No vibration or chatter Noticeably better finish than other bonded wheels of equal grain size Grinds smooth and quiet Cool cutting Won’t discolor or warp stainless Sigma Green is an aggressive grinding wheel with noticeably quiet and smooth grinding action. Our best selling grinding wheel is the perfect balance of fast grinding, low vibration, and superior finish. Sigma Green Grinding Wheels are fast grinding wheels manufactured with a specialty grain and bond combination. Sigma Green is constructed with a layer of coarse grain and a second layer of finer grain, resulting in a better finish compared to standard “fast grinding” wheels. The specialty bond also results in a better balanced, noticeably quieter, and much smoother running grinding wheel, with less chatter and less vibration.