My 84 S II barely will take the blue labeled Duracell non-lithium batteries. I actually had to squish them a bit with pliers to get them to fit properly into the compartment - no, not enough to cause a breach of the outer wraping. I have not opened the battery compartment of my 2003 bass, so who knows on that one. However, I just quit using batteries altogether in my S II's, as when do I ever plug in a 1/4 jack? Once a year to tune when I have my rack apart for cleaning, maybe? If the batteries are any larger than regular Duracell 9 volts, then I would expect them not to fit in the 'dual' battery compartments on mine. However, each instrument may be a bit different, as they are made by people, right?