... . 3.On/off switch 4.Many colors for option USB Cup Warmer And Cooler1.Keeps coffee/tea/drink warm at ... office used to warm and cool your drink.3. Use USB power, no batteries needed4.Easy installation, no driver required, safe ... switch.6.Different colors are available. Our major products:Headphones, speakers, radios, multifunctional items, toys, outdoor sports equipment, home appliances, household ...