The Canon RL2-0657-000 multi-purpose separation pad is a paper-feed replacement part for compatible Canon equipment. Canon’s parts catalog lists it among the internal components for the iR1643i/iR1643iF Series.
The pad is identified separately from the multi-purpose roller in the parts breakdown, as a distinct component of the paper-feed assembly. Its purpose is indicated by its name: it is the separation pad used in the multi-purpose feed area. This makes it a specific service part for that function, rather than a general-purpose accessory.