according to Kensington the light is an LED, and it only trains like 90 seconds of battery per hour, which seems pretty minimal.
I was just at the kensington site, and noticed the prices are $19.99...I have been looking to buy one of these for a while, but I thought they were way more expensive than this?
you could probably mod the light to use any color LED you like, green blue, red, yellow, white, purple, etc...this has to be one of the coolest things for lighting these days...you could even buy a bunch of them and a USB hub or two and put them all around a desk or similar for precise lighting...is the rebate limited to 1 per household?