I bought too many sets! Super cute colors and great for meal prep. Glass Quality: The Ello Duraglass containers are made of odor-free, stain-free, and clean tasting glass. Leak-Proof Lids: Features air-tight, leak-proof lids with extra thick silicone sleeves for protection against chips and breaks. Microwave & Oven Safe: Safe for use in the oven and microwave without the lid; no need to remove the silicone sleeve.