https://www.tripleclicks.com/18667815/detail?item=550705
Features:
USB powered, no batteries needed.
Plug and Play, no need to install extra driver.
Easy installation and easy operation.
Keep your hot coffee, tea, or other beverage warm, temperature range: 40 to 80.
Perfect for home and office using.

Specifications:
Color: black
Power: directly USB power
Working voltage: 5V
Item size: approx. 11 * 11 * 2.5cm / 4.3 * 4.3 * 1in
Item weight: 84g / 2.96oz
Package size: 19 * 13.5 * 3cm / 7.5 * 5.3 * 1.2in
Package weight: 112g / 3.95oz

Package including:
1 * USB Cup Warmer