A tall non-skid metal tray that can be stacked onto the Roto-Shake Genie's existing tray (supplied with product) to ROCK various containers including T-flasks, petri dishes, boxes, and sealed bags, increasing the capacity for rocking by double-stacking two trays. The stackable tray measures 305 x 305mm (12 x 12in) and CAN ONLY be stacked on the non-skid tray (0A-1100-070) supplied with product.