Two-in-one heat & steep design. For use as a stovetop kettle and tea steeper – heat water then steep tea all with one vessel. Develops full tea flavor. The high water to tea surface ratio allows tea leaves to fully expand and release optimal flavor. Premium quality glass. Made of hygienic, non-porous borosilicate glass. You’ll never worry about off-flavors, odors or toxins. It is the healthier choice for brewing tea and ensuring your tea tastes as pure as possible.