Rubbermaid 16061 Super stackable side load desk tray, 16-3/4w x 12-3/8d x 3-3/4h, black Rubbermaid Super Stackable Side Load Desk Tray. Self-stacking, no posts! Unique Stack-Loc feature keeps stacked trays together with locked-in stability. High-impact polystyrene. Self-stacking, no posts! Unique Stack-Loc feature keeps stacked trays together with locked-in stability. High-impact polystyrene. Holds big papers including computer printouts.