The link to them is in the first post they are cambro boxes any restaurant supply will have them. http://www.cambro.com/Food_Pans_and_...9490/1033.aspx
they are polycarbonate not acrylic. They are designed to fit into warming trays and are standard sizes. You may find what you need on the web site. Be warned sometimes you need to buy a set not just a few depending on what the supplier sell. Locally I need to buy 10 or more they are not super cheap.