OXO Good Grips Smart Seal Glass Containers are made from naturally BPA-free borosilicate glass, built to withstand extreme temperature changes without the risk of cracking or shattering. This means you can take your Smart Seal from freezer to preheated oven (or microwave) worry free. Their tight-locking lids have four secure tabs and a silicone gasket, for a leakproof seal that keeps food fresh and liquids contained. Designed to stack and nest, any combination of Smart Seal Containers can be organized to neatly fit your space.  Set includes: (2) 4 oz Rectangle glass containers. Dishwasher safe.