I think we went through this a long time ago. Google it and you may be lucky and find someone with a few left over.
It's an obsoleat item.
Some said they were using one of these to refull the one they already had. http://www.amazon.com/Soft-Firepower...d_sim_sbs_hi_1
joes right, ebay is your only chance. .if by chance you come across some cells more than likely they've expired. thats the problem with gas based nailers the fuel cells go bad over time. either by the fuel going stale or being stored in the cold too long the fuel contracts and slowly leaks out.. by that im talking 2 years or so