Tervis Gadsden Flag Don't Tread On Me Double Walled Insulated Tumbler Travel Cup Keeps Drinks Cold & Hot, 24oz Legacy Tervis tumblers feature double-wall insulated construction that keeps drinks hot or cold longer and reduces condensation to prevent rings on your table. Strong, impact resistant BPA-free material means these tumblers can take a tumble without shattering and won't retain tastes or odors.