concret floor pads are for polishing concrete floors. Use with floor grinders to repair or renovate old floors to get a new shine. The diamond floor pads are bonded with resin, velcro backing, high quality resin and diamond. the working layer thickness is 10mm, extra durable.
It's widely used for floor industry.
Available in 3 inch and 4 inch.
https://www.chinatoolscenter.com/floor-grinding-disc/