Store, heat and freeze meals, produce and ingredients with Bentgo's Signature food storage system. Oven-safe glass containers give you a clear view of contents, while the silicone-sealed tempered glass lids are airtight and leakproof. The lids' built-in steam valves allow proper venting and splatter-free heating for warming up foods in the microwave. The four-piece set comprises two round lidded containers in two sizes.