1, API Standard; 2, Designed for Oil&Gas Reservoir Fracturing; 3, L,M,H three series for differ usa; 4, ... Oil&Gas Reservoir Fractruing5.Material:Alumina Ceramic6.Density: Light-weight, Medium Density, High Density7.Standards: SY/T5108-2006, SY/T6302-1997,API ... Number:20-40, 30-50, 40-70, etcSpecifically designed for Fracturing.Ceramic Proppant. Ceramic Proppant