5" Heavy Duty Vinyl Faced Backup Pad This heavy duty vinyl faced backup pad is a medium density pad. It is 5 inches in diameter with no holes and uses PSA abrasives. The Mirka backing pads for sanding machines are designed to meet the challenges set when performing demanding sanding operations. Mirka has developed backing pads for both sanding with traditional abrasives and for sanding dust-free with Mirka's Net Sanding dust extraction system. In order to achieve the best performance and a good sanding result, it is important to combine the right sander with the right accessories. Browse our backing pads and find the backing pads suitable for your sanders.