API oil equipment Square Drive Roller Kelly Bushing

Square Drive Roller Kelly Bushing
The Square Drive Roller Kelly Bushing provides the following advantages:
1.Pulling out or feeding off string can be done while rotating;
2.Because of its whole construction, it can no fly out and hurts you.
3.The bushing is easily installed into the master bushing, maintaining good alignment;
4.The contact between Kelly and roller is rolling contact, so friction is lower, and weight on bit is accurate;
5.The Kelly has lower wear and has long life;