1.27-HDP Roller Kelly Bushing (Roller Bushing)is a necessary tool for drilling. 2.It is to drive kelly spinner by matching with master bushing. 3.Through rotating of four rollers, 4.the friction between rollers and kelly pipe is reduced and service life is extended. 5.For different sizes of kelly pipe and hexagonal pipe only need to change corresponding rollers. 6.To connect with rotary table, 7.there are two transmission styles (square and pin). 8.The product is designed and manufactured according to API Spec 7K "Specification For Drill Equipment" Our company owns a dependable quality administration system and has passed the evaluations of API Q1 Registration, ISO9001:2000 Certification and API Products Quality Recognition. Our products have the right to use the Official Monogram of API Spec 7K and API Spec 8A. We'll make our efforts to supply the best surface operation tools and drilling equipment for the oilfields in China and in the world. Model HDS27-HDP20-HDPMDS20-MDP17-MDPLDSType Heavy Medium Light Max. torque N.m323652255513729ft.lbf238711663610126Drive Mode Square Pin Square Pin Square Square mm76.2 152.463.5 133.3563.5 133.35in3 621/2 51/421/2 51/4Hex mm76.2 152.476.2 107.9576.2 107.95in3 63 41/43 41/4Size mm630*630*740630*630*780493*493*696510*510*720458*458*700508*508*700in24.8*24.8*29.1 24.8*24.8*30.719.4*19.4*27.420*20*28.318*18*27.520*20*27.5Weight Kg700730670420460340400lb1540161014709241012750808