ELMO - Power Pack 9V for Elmo Super-8 Sound cameras.

Made by Elmo for Elmo movie cameras that had the accessory plus for this power pack.  The power pack is simple - uses six C size batteries and plugs into your camera for extended shooting times.

NOTE:  Instructions say this will NOT work with Elmo models 300SL Macro, 600S, 600SD & 1000S Macro)

Looks never to have been used but box has wear.