Era Flip 30oz is the world's first 100% leakproof, covered, flip-down, straw tumbler. It has our fully leakproof SlideSeal lid that works for both cold and iced carbonated beverages, SoftSip silicone straw so every sip feels like a luxury, ColdKey metal straw for minimizing the amount of plastic sitting in your water, BevGuard technology to keep your drinks cold for 24+ hours, and a cup holder friendly base so you can enjoy your favorite beverages, free of leaks and spills throughout your daily journey. Made for stress-free sips.Era Flip 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.