Help keep your food fresher longer using Sistema Ultra Collection Round Food Storage Containers. Constructed out of ultra-clear Tritan plastic, this container is more durable than conventional plastic food containers. The screw-top lid creates a tight seal, but can be opened and closed easily with just a quick quarter turn and is designed for stacking. Tritan plastic is BPA-free, phthalate-free, freezer-safe, and dishwasher-safe on the top rack.