Go easy on the surfaces you're grinding with this Merit Zirc Plus Z/A medium grit TP (Type I) quick-change cloth disc. Its self-sharpening zirconia aluminum abrasive surface makes cuts with very little friction, which helps keep temperatures down and are designed to extend the disc's life on extra-hard surfaces. The durable 2-ply poly/cotton back provides a tough cushion that keeps jitter down and helps you make a clean cut, as well as giving you precise control over grinding against stainless steel, titanium, or miscellaneous super alloys.