Well, as I read it, it just means that there is only ONE cylinder roller bearing on each shaft at this end, and that it is a 'single-width' type; quite what they mean by that, I'm not qualified to say. I can only assume it must mean that the bearing has just one ring of rollers (the type I'm most familiar with, but maybe there are others?). Unless maybe in the same equipment there are other types of bearings that might be, for example 'double-width'. It might simply refer to the thickness [in the sense of: along the length of the shaft] of the bearing --- not all roller bearings are necessarily very long, but maybe this company uses them in different sizes.
Whatever, I feel sure it should be 'single-width' as one adjective describing the bearing, rather than 'a single' 'width-bearing'