leakproof Ü-Turn™ lid that works for both cold and carbonated beverages Era Tumblers are 100% leakproof with cold beverages and carbonated beverages with ice when in the locked position. Not recommended to be used in the locked position with hot beverages. ColdKey™ metal straw for minimizing the amount of plastic sitting in your water BevGuard™ technology to keep ice for 24+ hours, and a cup-holder friendly base so you can enjoy 30oz of your favorite beverage, free of leaks and spills throughout your daily journey. Capacity: 40oz