... bit 2.all kinds of models 3.long service lifetime Step drag bits, Drag bitsSpecificationsStepped three wings drag bitall kinds of ... as sand,clay or some soft rock.Type: Chevron and Step type Wings: 2, 3 and 4 wings Size: " to 24 ... 1/2", 6 5/8" API Reg. PinType: Chevron and Step typeWings: 2, 3 and 4 wingsSize: 3" to 24" Thread ... not hesitate to contact me,thanks.Sunny 101.6mm GREAT Step drag bits