Embodiments herein are directed to an inventory system having multiple inventory holders and drive units for moving the inventory holders. Features herein are directed to moving inventory items relative to a bin of an inventory holder or between inventory holders in the inventory system. The inventory system may include actuation units or some other mechanism on the drive units for assisting in moving inventory items relative to a bin of an inventory holder or between inventory holders. The inventory holders each include one or more inventory bins. A mobile drive unit is included, which includes an actuator configured for selectively actuating at least one of the inventory bins for moving at least one inventory item relative to the bin.