The double-walled borosilicate glass Funnex™ brews from 5 up to 15 oz. of CHEMEX®coffee. This unique brewer is portable, sturdy and highly functional. It comes with a silicone gasket for use with all types of cups, mugs and thermoses. The Funnex™ is perfect for brewing in the home, office, dorm room, on a camping trip – the possibilities are endless!