The Withdrawal Sleeve
is used when the bearing is installed against a shoulder on the shaft
and pushes the bearing against the shoulder while tightening. The
advantage of this is the bearing can be installed with the shaft out of
the machine since it is pressing against a shoulder, with the adapter
sleeve, it would be more difficult to position the bearing with the
shaft out of the machine since it is free to move on the shaft until it
is tightened.