* LEAK-PROOF and FRESHNESS PRESERVING: Snap-fit lid and sealing ring provide a tight seal. Perfect lunch box for fresh, yummy food for indoor and outdoor use.* COLLAPSIBLE and STACKABLE: The container is collapsible to 1/3 of the original size, about 1.2 inches, when not in use, and can stack on top of one another. Saving over 60% of space!* SAFER and ECO-FRIENDLY: Made from 100% food grade FDA approved Silicone. Non-toxic, tasteless, odorless, non-stick and easy to clean.* MODERN and DURABLE: Silicon bento box features high-strength and non-deforming. Applicable temperature: -40F to 446F. * NOTE: MUST open air vent before heating in microwave oven.