I think you guys miss the point of the device, it's actually a very rare prototype, that AE was developing. When there was no longer a need for the Crank and Magneto, AE figured that people would start to develop rather large left hands from holding the much heavier Receiver/Transmitter combination. So AE decided to attach an adjustable spring to the crank, so you could exercise your right hand and arm to match your left arm. The main flaw to the system was, the coffee cup and doodle pad were making up the difference in arm strength so it never caught on.
Very few remain, and are very rare. The spring was adjustable for greater tension.
D/P