We made a big ass 20oz glass tumbler for a technical reason. Glass has a thermal conductivity of 0.8 W/(m⋅K), which is a little more than 10 times that of plastic. So it keeps your iced coffee colder for 10 times longer than a plastic tumbler.
This custom tumbler is made from double-wall, high-Borosilicate Glass, features a push-on lid with a flip-top closure piece, includes a colored polypropylene straw that measures 9" in length, and a silicone seal ring to prevent leakage, and keeps the lid in place. Designed to fit into most cup holders.