MOSTOP&reg; Multi-function Mouse Mat Calculator 4 Ports USB 2.0 Hub with Blue Mood Light (Multi-function Mouse Mat) Multifunction work as computer mouse mat /pad, calculator, USB hubs. Simplicity style, frosted smooth surface, no prominent button. Anti slip base design give it protection. Super thin 7mm; With cool blue mood LED light. USB 2.0 hub (one input and three output) for devices power charging or indirect data transmission. Power Supply DC 5V and battery built-in a button cell battery.