3M Radial Bristle Discs are long lasting and very effective. Stack them on mandrels and use them like natural bristle brushes – except there is no need to add polishing compound. The compound is built in! Simply stack the individual bristle discs on a pin hole mandrel – use one disc or as many as you can fit – four to six make a good brush – and you are ready to polish. You get a very flexible, long lasting polishing brush that never needs recharging. 3M radial bristle disc brushes are also cool running to help prevent damage by heat build up, and give an easy to control uniform finish.