This notebook pad by evercool is a light and portable solution to cooling down your notebook. No batteries or external power source is necessary. Just connect into thye usb port and your lap top will be cooling down in no time!! F e a t u r e s: high performance with 4 built. No external power necessary. Usb interface for power .Light and portable design. Low power consumption. Smart fan control. S p e c i f i c a t i o n s: fan dimension: 60m x 60m x 10m. Voltage: 5vdc(usb) .Current: .40A. power: 2w. Fan speed: 1900 - 2600rpm. Air flow: 40cfm. Noise: 24dba.