I was also looking for one a few months ago and after emailing multiple LBS and Specialized retailers, the only place I could find was Carolina Triathlon in SC. (They Ship within the US)

I have the Fuelcell but it was missing the mounting attachment so I had to buy another one.

I would contact Specialized Rider care. They should be able to help you out.

I have one, never used, PM if interested.

sent PM

Thank you all! I have heard they are hard to come by and haven't been able to find any via LBS, Specialized, etc.