Food-Grade Materials: Made Of Food-Grade Wheat Straw Plastic, Bento Snack Box Containers Are Bpa-Free And Reusable. They'Re Sturdy Enough To Last, And Safe To Use In Microwave, Dishwasher, Refrigerator. The Boxes Can Stack Nicely When They Are Full With Food And When They Are Empty, They Nest Inside Of Each Other For Storage To Take Up Less Space. | | Compartment Separated: Snack Containers Are Designed To Be Compartments Separated And The Lids Have Depressions Where Each Of The Compartments Are To Help Keep The Contents From Migrating To Other Compartment, So Smells Can'T Spill Over Between Compartments During Transportation. Note: Lids Seal Nicely But Not Leakproof, Snack Box Should Be Kept Upright. | | Portable Portion Size: Bento Snack Box Measures 6.58'' X 5.95'' X 2.09'', Which Is Portable And Lightweight That Work Great For Lunch Or Snack On The Go. And The Compartments Have Clearly Defined Portion Size To Provide A Good Solution For Making Portioned "Snack Packs" .