1.Tricone bit,rock bit,oil drill bit 2.certified by ISO. 3.28 ... (r / min)5120.35~0.7120~60mud stone,plaster stone ,salt rock ,soft shale ,cotton rock5420.4~0.8100~60Medium soft shale ... ,medium cotton rock ,medium-soft sandstone6120.5~0.9100~60argillite,limestone,sandstone,dolomite ...