The IonMug Stainless Steel in black keeps drinks hot - but not for the time stated. Says it will last two hours but it don’t last that long. But if your coffee is still sitting in the mug after two hours you probably don’t even really like coffee. Durable, easy to clean. Doesn’t fit in the cup holders in the car. Just FYI. The product is ok.  It’s useful but you probably won’t be wow’d.