... 3.Meet with API Spec7-1 Standard The main products we manufactured are bellows 1, tricone bit include the steel tooth and tung , we ... is four to twelve, the size is 8-1/2”, 9-1/2”, 12-1/4”, 6”, 17-1/2”,4, the Rotary speed is form ... 10 ~300 r/min.We have the stock of the main ...