This 12oz. self-heating coffee mug has three adjustable temperature levels: 135°, 140°, or 145° F, with a built-in rechargeable battery that keeps the beverage perfectly warm for up to 2 hours. It also has an auto-shutoff safety feature after 3 hours of charging the coaster. The price drops from $57.99 to $24.88. Shipping is free on orders above $35.