It stacks up as a smarter space efficient, multi-functional storage set. This set of four square tempered glass covered storage containers by Stax Living is designed to enhance your healthy, on-the-go space efficient lifestyle. this multi-functional tempered glass set allows you to serve and store food – all in the same containers – saving you cleanup time and effort. The orange hand-shaped vacu-seal on the lid provides two helpful functions. Put the vacu-seal in the up position and it works as a microwave vent, trapping in moisture and nutrients for juicy and healthy microwave cooking results. And to keep stored food fresh longer, put the lid tightly on the tempered glass container with the vacu-seal in the up position to remove excess air. Then close the vacu-seal for a perfect seal. This tempered glass storage set is made for safety. Tempered glass is a safer alternative to plastic containers. Durable and shatter-resistant, it can withstand the abuse dished out by daily usage as well as casual entertaining. If the fully tempered glass should break when dropped, it will break into small pieces with no sharp edges to minimize risk of injury. When not in use, this Stax Living rectangular tempered glass storage set nests completely with the lids on to maximize your storage space and fit your life. No more missing lids! It is just one more way that Stax Living fits your life. They are ideal for everyday dining, casual entertaining, as well as on-the-go events like potluck dinners.