The Segway Drift W1 user manual is online:
http://www.segway.com/media/2451/18-...1um-_final.pdf
A few interesting points...
Battery size: 44.4Wh
^-- this means that you can actually take these on planes, right? The two skates combined would equal roughly the size of an extended-life laptop battery.
Distance: estimated 3.75 miles (160 pound rider, 5mph, 77F, flat ground)
Maximum weight: 220 lbs