Still lighter, and considerably more economical than the motor drive assembly, the Winder 2 gives speeds as fast as 2.5 frames per second - probably the best performer in its class. You can select either Single or Sequence mode, and of course shoot at any camera shutter speed, as with the motor drive. In fact, the Winder 2 has a whole lot of full-fledged motor drive sophistication. It takes bulk film with the 250 Film Back 1, permits wired or wireless remote control, and even provides a seperate M.6V Power Pack 1 for use in extreme cold conditions. Weight is a mere 10.2 oz. without batteries. The usual power source is four "AA" batteries, loaded in the "snap-in" type M.6V Battery Holder 1.