Plug-a-Mug 12 Volt Heated Coffee Mugs - Dual Pack! 2 - Insulated stainless steel 16 oz. mugs with covers (blue & red) 2 - 12 volt plug-in auto adapters Will not overheat or burn liquid, non-skid base fits all standard cup holders Insulated stainless steel mug keeps cold liquids cold, hot liquids hot Hand wash only