1,all types of oil and gas well drill bits 2,certifide by ISO 3,wide size code 4,best price 5,delivery on time Quick DetailsPlace of Origin: Hebei China (Mainland)Brand Name: BaoxingModel Number: SKG214Type: Center Drill BitMaterial: High manganese steelUse: Well Drillingsize: 9 5/8" 244.5mmPin shank size: 6 5/8regNormal WOB(bit dia): 0.25--0.70KN/mmRotary speed: 200~80r/minTypes of Bearing: ...