Standalone mac battery charger

Got a spare mac battery? I've often wondered why up until now no-one's produced a standalone charger so that you can charge batteries without having to plug them into the mac. Fortunately Fastmac.com have produced a standalone charger that allows you to do just that. and it's compatible with iBooks, Powerbooks, macbooks and Macbook Pros. It's also 110/200v. Exactly what I was looking for!