Brew your favorite tea on the go! Easily brew loose leaf tea in this Zoku glass core bottle. The infuser is made from stainless steel, and is easy to assemble and clean. On-the-go brewing solution Borosilicate glass bottle made of durable 18/8 stainless steel. The fine perforation prevents tea leaves from falling into your drink, and produces cleaner brew. The silicone gasket keeps your infuser leak-free and in position.