As seen on Shark Tank, these 100% food-grade silicone, BPA-free freezer trays are in conveniently portioned sizes and can be stacked in your freezer. The lids are made from Polypropylene Plastic (PP), which is also BPA free. Both the trays and lids are dishwasher safe. You can also bake in your Souper Cubes® — the trays are 100% oven-safe up to 415 degrees Fahrenheit. The lids are not oven safe, however.