An apparatus includes a housing, a rotatable spool disposed within the housing, a belt at least partially wound onto the spool, a motorized retraction mechanism disposed within the housing, coupled to the spool, and configured cause rotation of the spool in a first direction for winding the belt onto the spool, and a tensioning mechanism disposed within the housing, coupled to the spool, and configured to prevent over-rotation of the spool in a second direction opposite the first direction while the belt is being dispensed from the spool.