The present invention is a stacker unit having an inlet area with sensors to detect ingress of a hamper or similar nestable container whereby a plurality of parallel lifting elements complimentary of the container, may grasp the container and lift it to perform a stacking operation when combined with a plurality of stacked containers. The inlet area has a plurality of walls providing structure and mounting for sensors and controls for selecting containers having an open end forming an entrance, within said entrance a plurality of guides, lifting elements and adaptors are actuated upon detection of an incoming container operable in lifting said container for stacking by utilization of a chain drive and motor having adjustable plates coupled to said lifting elements. It is also capable of lateral adjustment to suit differently sized containers utilizing attachments for the lifting of hampers, wire containers and 084C containers along with having a plurality of lockout controls for better control and safety precautions while operating a lifting and stacking procedure.