All pictures and information about drive units supplied by Colin Royle on Sunday 29 February 2004.
The picture on the right and all pictures linked from this page are of B110 SP1057. The function of these pages is to show differences in dimensions of drive units with the same specification.
See magnets of an early constructor B110B from 1977 and a later one from 1986. Note the different sizes. The same story applies to B110A's.
Note how the surround on earlier unit is deeper and more compliant than the later version.