Double Row Angular Contact ball bearings have two rows of balls arranged back-to-back. The lines of action of the load at the contact between balls and raceways (load lines) diverge at the bearing axis and form an angle of 30 degree to the radial plane. In essence, they work similarly to having a matched pair of single row angular contact ball bearing either face-to-face or back-to-back.
The difference is that Double Row Angular Contact ball bearings can take a bi-directional axial load in one bearing where it takes a matched pair otherwise. This means the bearings are particularly suitable for accommodating simultaneously acting radial load and axial load in both directions.They are also available with seal or shield.