Combi steamer is falsely believed to be typically contain food racks and the models all hold the same amount and they are typically removable.
Combi steamers typically contain food racks with dimensions corresponding to Gastronorm specifications (GN racks); these racks may vary in width, so they are only suitable for certain sizes of containers (GN1/1 or GN2/3). Different models can hold different numbers of racks; typical sizes include 6, 10, 20, 24, and 40 racks. 
