I don't have a reason to keep this any more since I upgraded to a 6kg tank. I recently got it filled as a spare but if anyone is on the lookout and has €35 to spend, let me know.
It's a standard co2 bottle that fits a normal regulator like the one Norm supplies.
If no one is interested then I will just keep it as a spare.
For newbies looking to get in to kegging and wondering how long it will last. It depends. If you naturally carb like myself and only use it for top up pressure then it can easily last you a year before you need a refill. It could even last over 2 years, That is going on my experience where I filled up in September 2009 and did not need a refill until February just gone. This from a two keg kegerator averaging 2 pints a night almost every weeknight for 2 years plus a good few more at the weekends.
The trick to making it last that long is to only turn it on and attach the disconnect to the keg when you want to give it a 20 second blast.
It will not last as long if you leave it connected and turned on. Nor will it last as long if you force carbonate.
If you want something small that will fit inside a kegerator then get something like this. Otherwise, get a larger 6kg one like my new one from Leinster co2 (or Munster).