A bearing or bushing can be used for linear or rotational motion. While most bearings and bushings are designed for only one type of motion, there are some parts that can combine both. NB stroke bush products, for instance, have raceway grooves along the axis of the shaft, same as NB’s regular slide bushes. But between the ball retainer and the outer casing, there are rotational ball circuits as well that allow the entire retainer and shaft to rotate within the stroke bush unit. This is just one example of the various types of bearings that can combine rotational and linear motion. Allowing for this motion though often requires a larger unit than other bearings relative to the size of the shaft.