OXO Good Grips Smart Seal Glass Containers do more than just keep food fresh. Made from naturally BPA-free borosilicate glass, these durable containers are built to go from freezer to pre-heated oven-or microwave-without the need to fully thaw. The 4-cup capacity container is perfect for sides and leftovers. Four locking tabs work together with the silicone gasket to create a leakproof seal, perfect for taking food on the go. Smart Seal Containers stack conveniently in your fridge or freezer and nest neatly in your cabinet. Dishwasher safe.