1.aluminium oxide,silicon carbide or zirconium oxide 2.resin over resin 3.vulcanized ... Sanding Paper Disc:Vulcanized Fiber Disc,1)abrasives:aluminum oxide,silicon carbide,or zirconium oxide;2)mainly used in ship,automobile,aviation ... relevant parameters:SPECIFICATION CAP QTY.(pcs/carton) CARTON SIZE N.W/G.W 4″ 16 500 23×23×35 12.00/14 ... 60-120 400 39×39×18 20.00/22.00 silicon carbide Sand Paper Disc