(Borosilicate Glass Material) The storage containers made of borosilicate glass material have excellent heat resistance, strong strength, and have improved heat resistance, water resistance, and acid resistance compared to traditional glass. Heat Resistant Temperature: -4F to 104F (-20C to 400C) If you remove the lid, you can use it in a microwave or oven(Excellent Sealability) 4-piece locking sealed food storage containers and sealing for a secure seal. Even if the container is turned upside down, it will not leak. Even if you put foods with strong acid or salt, Wide range of uses: Can be used for a wide variety of purposes, such as food, fruit, dry goods, etc. Can be used for commuting to work, school, travel, flower viewing, etc(Easy to Organize & Safe to Use) The containers you can see the contents and organize them easily. It is made of glass and does not contain harmful ingredients, so you can rest assured that you can use it