【2-in-1 Smart Temperature Control Mug】- Smart Mug has both hot and cold functions, you can enjoy cold drinks in summer and hot coffee in winter, whether traveling, working or outdoors. Two buttons, red LED light for HOT mode, heated to 140°F, blue one for COLD mode, coldest at 21°F | 【Compatible with Most Coffee and Beverage Bottles】- Ergonomically designed to fit most vehicle cup holders. Suitable for hot water cups, coffee, tea, beverages, etc. whose length is less than 2.8IN. Our coffee cup thermostat is suitable for bus, truck or car | 【Safety Protection System】 - Passed ROHS Certificate. Automatic shutdown to protect car battery when voltage <10.5V | 【Easy to Plug and Play】- Just connect directly to the cigarette lighter through the adapter cable when using, the general base size of most cars is less than 2.75 inches | 【Best Choice for Gifts】 - Innovative and superior quality, our heated coffee mugs are the perfect Christmas gift for family and friends, colleagues, Thanksgiving gifts or birthday gifts. If you have any questions or concerns about this item, please contact us for free on the order page, we promise to give you a satisfactory solution