Eircom Phonewatch Key Fob Battery

Hi,
would I find a battery for the eircom phonewatch key fob in my local jewellers and is it straightforward to change? I cannot find any links to this question on the web. I do not want to go to Phonewatch for obvious reasons. Appreciate any help.
Max

See

http://www.askaboutmoney.com/showthread.php?p=737011

Thanks for your reply. I found the answer. The key fob batteries are duracell MN21 or Energiser A23 which I bought in Dunnes stores.
Thank You