Petri Dish Racks To help you sort, stack and store your Petri dishes we offer a range of 3 sizes of wire rack: 10 plates, 20 plates and 30 plates. All racks are manufactured for easy cleaning and durability. Our racks are ideal for using in workstations. Product Codes 10 Plate Petri Dish Holder - Code A02534 20 Plate Petri Dish Holder - Code A02718 30 Plate Petri Dish Holder - Code A00210