This is a 16 mm movie camera equipped with constant speed, spring motor mechanism with an 8:1 external drive shaft permits the attachment of an electric motor (as is the case here in the rectangular black box fixed on the side of the camera); a 6x magnification viewfinder, variable speed selections; a 144 degree shutter; footage and frame counters; an audible footage indicator; single frame option; manual rewind and tripod socket.
The camera is mounted on a metallic plate side by side with an electric motor.
This information was taken from the following very useful
website.