The HPO series is especially designed for high speed outer race overrunning applications, such as high speed dual drives or standby drives. HPO clutches are grease lubricated and equipped with labyrinth seals. Formchrome® sprags and special retainers are incorporated for maximum service life and speed capability. These clutches mount on a through shaft, with the inner race driven by a key. The ground O.D. of the outer race is designed as the mounting surface for attaching parts and is concentric with the bore. Tapped holes are provided in each end of the outer race for securing parts to the clutch.