Size: 4",4.5",5",7". Thickness of Fiber Paper: 0.8-1.0MM. Grit: 16#-120#. Abrasive Material: Aluminium Oxide. Used for wood or metal. Closed or Open Coating with Electronic Sanding Planting. Hole Type: Round or Cross Quality is Good and Stable. 25pcs/shrink,400pcs/carton.