... material,ceramic sintering,is a natural quartz sand,glass balls,metal balls and other low-strength proppant in the alternative,the ... ,0.212-0.425 mm,0.3-0.6 mm etc. 3.Specification (Size) : 20/40 mesh ; 30/50 mesh ; 40/70 meshOther special meshes ... mesh,12/18 mesh,12/20 mesh,16/20 mesh,16/30 mesh,30/60 mesh,40/60 mesh,70/100 mesh etc4.Color : color:yellow,dark grey,black ...