Gastronorm sizes are standard sizes of containers used in the catering industry specified in the EN 631 standards:
Trays and stackable stainless steel are specializing in food process, polycarbonate and polypropylene are good for storage while melamineware are good display solution. They are made in these sizes especially for the catering industry.There are also covers is same measurements , GN 1/1 , GN 1/2 , GN 1/3 , GN 2/1 , GN 1/4, GN 1/6 , GN 1/9 , GN 2/3.
References
Gastronorm sizes Wikipedia(Text) CC BY-SA