The OXO Good Grips Smart Seal Glass Set includes our full Smart Seal line, so whether you're reheating frozen lasagna or bringing a carefully prepped lunch to work, you're covered. Thoughtfully engineered lids come equipped with a leakproof, spillproof and worry-proof silicone seal that's easily removable for cleaning, plus four locking tabs to keep food secure. Smart Seal Glass is made from durable, naturally BPA-free borosilicate glass, so it can go from freezer to (preheated) oven without cracking or shattering. Smart Seal containers stack neatly in your fridge or freezer and nest in your cupboard when not in use. Lids are interchangeable between the Glass and Plastic lines