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But not all of them, see attached manual page. Some used 3 volts supplied from a flashlight size battery case. There are bulbs that fit the socket in 3v, 6v, 12v, and 24 volt ratings so you can make up a battery pack that you want and then just put in the proper bulb. Three "AA" put out 4.5 v and work well with a 6v bulb and is very compact, I velcroed such a power supply to the back of my MA-2. If you want 28 volts then three 9volt batteries in series will get you there. If yours has the electronic averager which uses a lot of power then this doesn't work too well since the averager eats batteries, better to use a 24 volt tranformer available at Home Depot or Lowe's  for your sprinkler system, very inexpensive. I also posted how to make a 28 volt source powered from a 12 volt car socket, costs about $30 and is simple to make. I have posted a lot of information on this in the past so just research the archive. 

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The Kolsmann bulbs are 28V, but fairly readily obtainable. You may still need the bubble light during daylight to get a good balance between the target and the bubble. You could use any handy 24v dc or ac power supply to run it. The 9v batteries wont last any time.

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