The other day I found a lovely little Brownie Hawkeye Flash at my local thrift store. Now I'd like to outfit it with a compatible flashbulb unit, and the only one that looked in good condition was a Kodalite IV. It's not a big unit, about the size of a large hand. There are some bigger ones but they are rusty and one has leaked batteries in it. I'm tempted to get the Kodalite because it's cheap and in good condition. Does anybody know if... * I need special AA batteries for it? There are some old (but not leaking) Rayovac ones in it that have a "Photoflash" mention. Would ordinary ones do the job? * What is the difference between M2, 5 and 25 type bulbs. Yes, I scoured the net about them, and J&C sells them, but I couldn't find a clear distinction between them. Which is the strongest one? I'm pretty excited about this: 120 film on the load spool with a 620 takeup spool is a go; I got three extra 620 spools, and now if I can outfit a flash on it, I'll be a happy camper for Christmas photos!