Each section of the Petri Dish Desk Holder (Cat. No. 1814 & 181) and the Revolving Petri Dish Holder (Cat. No.184) holds 13 Petri dishes. Revolving model rotates 360°. Ideal for separation of cultures from different sources. These racks store conveniently in the corner of an incubator. Made of durable and easy to care for acrylic.