... compacted shales ,sandstone, clays, salts and soft li mestones. Size and IADC available: 3 3/4" to 26" IADC 415,435,445, ... /8”)212.7mm(8 3/8”),215.9mm(8 1/2”),222.2mm8 3/4”) 241.3(9 1/2”),244.4(9 5 ... /4”),346.0 (13 5/8”),349.2(13 3/4”)374.6(14 3/4”)381(15”),393.7(15 1 ... )Brand Name:kingdreamModel Number:HAType:Center Drill BitGuarantee period:2~4 yearsUse:Well Drilling Rotary speed:300~80r/minTypes of ...