This is the ideal accessory for people work long hours on the computer and don??™t want the coffee/tea get cold. The special insulation material around the metal plate prevents burns from other objects. This USB powered warmer combined with a 4 port hub will allow one to keep drink warm while powering any other USB devices needed through 4 extra USB ports. Av Lab recommends using tall tea or coffee cups with 2 ?? or 3 inches base to regulate the best temperature. USB cup warmer goes perfect for your desktop/laptop computer. The USB-powered warmer is plug-n-play, no driver is needed. Keeps your beverages warm between 50-60 degrees. The best of all, its is also a 4-port USB hub. Simply plug this device into a spare USB port onto computer and turn on using the power button. Within seconds will be able to feel the heat from the warmer and within 2 minutes it will be at the ideal temperature to keep drinks ...