Tall non-skid metal tray accessory that can be stacked onto the original Roto-Shake Genie tray to rock various containers including T-flasks, petri dishes, boxes, and sealed bags. Accessory tray increases the capacity for rocking by double-stacking two trays. The stackable tray measures 305 x 305mm (12 x 12in) and is only for use with the non-skid tray that is supplied with the Roto-Shake Genie. For use during rocking procedures only.