Product review (5 stars): I only wish they had designed these better; if the rollers themselves had the tabs and ...
Replaced the part that broke.  Works perfectly.  I only wish they had designed these better; if the rollers themselves had the tabs and inserted into this part, the replacment part would only be a few cents.  I've had the tabs break, and therefore the rollers fall off on at least 4 of these.  Poor design, espically since you have to replace this whole part instead of the small rollers when this happens.