These Blue Spot Sanding Flap Discs are suitable for efficient stripping and sanding of metal and wood surfaces. They are ideal for finishing. This 3 piece set includes the following 40 Grit, 60 Grit and 120 Grit. Each sanding flap disc has the following specifications Diameter 115mm. Bore size 22.2mm. Max speed 13,300/min, 80m/s.