Oh, I know this! The phrase just conjured in my head the image of wind-up toys.Nearly all camera shutters are "spring driven" and have been for almost two hundred years... ??? On most cameras, the action of the film transport also tensions the shutter main spring; older cameras and view cameras with mechanically timed shutters have a specific shutter cocking lever to tension the shutter main spring.
What has changed on modern shutters is that the shutter's timing mechanism is more usually controlled by electronic means, but this does not change the fact that the shutter is "spring-driven" ...
G
Well,$300 would be an awesome price for this, but given the ISO 800 speed of Instax film, and the camera's 1/300 max shutter speed, I might set aside a few extra $ for neutral-density filters.
.... or "expired".
DPreview says they were quoted $300 but perhaps that was a mistake? In the following video, it seems as if the representatives were struggling a bit with English. Lens, shutter and struts appear to be Seagull 203 (I hope none were sacrificed!), which would suggest shutter speeds of 1 sec - 1/300 and B, and the prototypes appear to have a functioning coupled rangefinder.