The Roller Kelly bushing ia a necessary tool tor drilling, by matching with the rotary square to drive Kelly pipe. The product can reduce its friction with Kelly by rotation of four rollers and extend its service life. Change different rollers to match with different square and hexagonal Kelly pipes and connect with different rotary tables. Two transmission styles(square and pinconnect)are available. The product is designed and manufactured according to API Spec 7k'Specification for Drill Equipment.