Northwestern 12 oz Tervis Tumblers - Set of 4 by M.LaHart Show your Wildcats pride with our Tervis insulated Tumblers! Double walled construction keeps your hot drinks hot, and cold drinks cold longer. 12 ounce capacity. Made of high grade polycarbonate; the same material used in bulletproof shields. Crystal clear clarity that does not scratch or discolor. Lifetime guarantee.