I hope someone can help. I got my remote back from the detailer without a battery in it. I am not sure why but I have gone back and complained. Anyway, I do not know what battery it needs. This is not the large remote that uses the 4 small bateries like it shows in the manual. This is a smaller remote that you can attach additional keys to with a ring. On the back of the battery compartment it says FBS2A and on the circut board it says FBSX. I was unable to match these identifiers up on any battery conversion charts. Does anyone know what batteries it requires. Thank you.