With Tupperware's Stacking Thermal Containers you can enjoy healthy hot or cold meals/snacks on the go. This product is ideal for people who lack access to a fridge or microwave oven outside the home. By stacking them, meals can be customized for perfect portioning control throughout the day. The stainless steel double-wall vacuum container, combined with the one-size-fits-all watertight insulated cover, help maintain the temperature. By pushing the cover valve, air escapes and releases the pressure inside for easy opening. Special connection points (on base and cover) interlock for easy stacking. The wide opening allows for easy filling and eating.