The Premier Metal Art Tray (36") by Studio Designs is constructed with durable, powder-coated, steel. The 7/8" U-shaped opening accommodates most of our Studio Designs tables or any tabletop between 3/4"- 5/8" thick. This workspace organizer features an oscillating mesh cup and deep compartments for your art supplies. It can be mounted to the rear of most art tables. You also get two removeable Flexible Foam Organizer Trays" (also sold separately) to keep your pencils, brushes and markers in order and a cell phone slot to keep your phone clean and close during your projects. Also available: The Premier Metal Art Tray -24" (Item # 12167), Premier Metal Art Tray 42" (Item # 12169) Other accessories available: The Flexible Foam Pencil Organizer, 2-Pack (Item # 12174), Flexible Foam Marker Organizer, 2-Pack (Item 12173) and Flexible Foam Jumbo Marker Organizer (Item #12175)