SKF Self Aligning Ball Bearings:
This bearing series has two rows of balls running on the same spherical outer raceway, this makes the bearing self aligning, self centering and insensitive to angular misalignment. They are particularly suited to applications where considerable shaft deflections are anticipated. Self aligning ball bearings have the lowest rolling friction of all rolling bearings and are the coolest running bearing type even at high speeds.
Benefits: Tolerates misalignment, cool running, self centering