SKF offers two main families of double direction angular contact ball bearings: the series 2344(00) and the series BTM.
These bearings are able to locate a spindle axially in both directions, and are intended for mounting at the side of the double row or single row cylindrical roller bearings of series NN 30 K and N 10 K. The outside diameter of the housing washer is made to tolerances to ensure sufficient radial clearance to the housing bore.

Bearings of the series 2344(00) have a contact angle of 60°. The preload, the considerable contact angle, together with a large number of balls and the specific cage assembly impart high axial stiffness to the bearings.
The series BTM allows a higher speed capability although the ability to resist axial loads is lower than the 234 series.

The bearings belonging to series 2344(00) are of separable design: they have a one piece housing washer, two ball and cage assemblies with a large number of balls and two shaft washers separated by a spacer sleeve. When mounted the bearing become preloaded. They have a contact angle of 60° and, to facilitate efficient lubrication, they have a groove and three lubrication holes in the housing washer.

The preload, the 60° contact angle, together with the large number of balls and cage assembly impart high axial stiffness to the bearing. The specifically developed cage design makes them suitable for relatively high-speed operations.

Bearings of series BTM are non-separable and designed as single direction angular contact thrust ball bearings, although always supplied in back-to-back sets, and are able to carry thrust loads in both directions. When mounted the bearings become preloaded.

The bearings have a contact angle of 30° and 40° and the same bore and outside diameter as series 2344(00), but a 25% lower sectional height (width), which makes them particularly suitable for very compact arrangements.
They do not have the same high load carrying capacity and axial stiffness as those of the series 2344(00), but can operate at higher speed.