1)API standard 2)competive price 3)professional service 4)Good reputation from registered customers 5)Delivery on tim ModelTCI BIT, STEEL TOOTH ... typeFormation or layer soft ,medium soft ,hard,medium hard,very hard formationButton size (extra features)Button bit,saw teeth1) Y-Conical teeth 2) X ... anti-abrasiveMy Skype:angela257000Any question,please contact us! API-5DP standard drill pipe