Made Of Polypropylene Suitable For Food And Harmless For Human Health. The Box Keeps Dough Fresh Inside And Makes The Dough Fermented. The Trays Are Stackable With Or Without Lids. The Tray Is Not Heavy Itself To Handle, Round Edges Makes It Ergonomic Suitable To Handle. The Trays Are Dishwasher Safe, So They Will Not Bend, Sag Or Lose Their Shape. Solid Surface Design Makes Our Pizza Dough Trays Easy To Clean And Reuse.