This is a Phantom Lithium-Ion battery: it is 12v 9a and is just 4.4x3.5x2.28 inches and weighs about 1.5 pounds. According to the literature this battery is quite capable of cranking the starter on big twins! It was a real find and you can see more images and details on my album at: http://www.motoredbikes.com/album.php?albumid=1973. I designed and had the bracket built at a local machine shop, but MSiert (Murray) in Omaha and I have tag teamed on the battery and bracket for the past few weeks. You can see his bike and installation as well in the album area at http://www.motoredbikes.com/album.php?albumid=1978. The whole package fits nicely in the space behind the seat post and is rock solid and has been a steady 13.35 volts for the past few weeks with temps in the twenties. Right now it only powers my Suzuki horn, but adding any LED device would be a snap and put little drain on the unit.