AA...... you could have just opened the wii mote to find out also a quick google search would have found it easily, there is also a whole heap of maunals you get with your wii which would have also told you. NEXT TIME DO SOME QUICK RESEARCH FIRST.
I would recommend AA since thats the size that your replacing.
You know the size that came with the Wiimote and then came out when you went to replace them.:idea:
