good suspension, thixotropy, filtration a small amount of mud good performance, configuration, convenient features RequirementStandard Suspension properties Viscometer dial reading at 600r/min Min.45.0 Yield point/plastic viscosity Ratio Max.3.0 Filtrate volume Max.15.0 cm3 Residue of diameter greater than 75um Max.mass fraction 4% Crossing directional bentonite