Thick outer ring: The mast bearing runs at a relatively low speed. As track bearings they run along the track to bear high loads. The outer ring of the mast bearings is much thicker than standard bearings to transmit this load.
One-piece design: The components of the bearing are fixed together to form an indivisible “wheel”.
Balls or rollers: Due to high loads, mast bearings usually have balls or rollers as their rolling elements.
Sealing: Mast bearings are usually sealed to prevent grease from spilling and to prevent debris from entering. The seal can be rubber (RS) or metal (ZZ).