A silicone-wrapped interior steel rim gives the tray strength while individually molded cubes with easy-to-read measurement markings easily pop out when you're ready to thaw. Premium-grade pure silicone body and Bpa-free lid keeps food as fresh as possible with an area for marking contents that also keeps freezer odors out, the tray is even microwave and oven safe up to 425°. Tray and lid are sturdy and dishwasher safe.