Sanding pads for hook and loop and vinyl discs. Underlaying pads into excentrical grinding machines OPTIMAtools. bottom disc is made from shock-proof synthetic material and foam on the top is from high quality polyurethane. Hard: High edge´s strength. It is used for flat surface and narrow edges. Its characteristic is resistance against ripping, oil and aging. Medium hard: For universal use, for flat and curved surfaces. Its characteristical is resistance against ripping, oil and aging. These sanding pads satisfy demanding requirements. 8 lateral holes are connected with the ninth central hole by channels for better drainage of abrasive particles. Hard-13-16mm.Medium soft: 13-16mm.