A sorter system includes a first conveyor for transporting items to designated containers, a second conveyor for transporting containers containing the items, and a shuttle unit. The shuttle unit may include a base defining a loading area proximate to the first conveyor and a staging area proximate to the second conveyor and a tray disposed on the base for receiving containers on a first section and a second section. The tray may be movable between a first position in which the first section is in the loading area and a second position in which the first section is in the staging area. The shuttle unit may further include a transport device for selectively moving a container on the first section of the tray from the staging area onto the second conveyor.