Can you guys tell me what is the battery type for the RDX key? Aparently my wife is getting the "change battery in key" message . I want to buy it on my way home. Also any instructions on how to open the key fob would help. Thanks guys.

 

The battery (for my 2013 RDX) is CR2032. I don't know if it is the same for other years. To open the fob, pull out the "key" part and you'll see an indentation in the fob that you can open by using a coin or screwdriver and twist it apart.

 

Check this out:

 

Thanks guys. Yes my battery is the same CR 2032.
The key feels so low quality though. Wish I could transplant the internals to the shell of a newer RDX key. I couldn't find any of those on the market yet.