A device for singulating open-ended objects includes: a housing configured to retain a plurality of open-ended objects, the housing having an open lower end; an outer ring positioned below the housing; a drum positioned within the outer ring to form a drum assembly, the drum including a hub having a substantially circular wall and a plurality of wings that extend radially outwardly from the wall to contact the outer ring, the hub, wings and outer ring forming a plurality of gaps; a mounting structure with an exit aperture fixed relative to the housing; and a rotary drive unit mounted to the drum that rotates the drum about an axis of rotation. The presence of the wings can enable the device to singulated caps more consistently.