Hi, I recently got a new bass guitar. A Yamaha XBS-375 or something like that. Bassically when I got it, At the back I opened the battery compartment up and removed the battery, it sayed it was dated march 2006..So Im guessing it must have been in there a long time. So I wanted to get another replacement..but Im not sure if that battery is a special one or not? Can get just a normal 9v square duracell or ennergiser battery? is it ok? or do I need something special? I looked for information on the battery..but it just says 9v? please help me.