Officemate Unbreakable High Capacity Trays, Set of 2, Black (21072) Trays can stacked with top tray across bottom at 90 or at normal 180. High capacity. Posts included are 1", 3" and 5" long so trays can be stacked at varying heights Unbreakable plastic material- Set of 2 trays plus posts Trays can stacked with top tray across bottom at 90 or at normal 180.