This handy little gadget was produced by Spectra Astro Systems.
Vibration Free Shutter-replaces the awkward "hat trick" to shield your film from unexpected headlights, satellites,planes or clouds. Also allows one to take a break during a long exposure and then resume guiding.
Heres how it works:
Inserts into any telecope with a two inch focuser. T-threads on the other side attach to your cameras t-ring. Simply attach camera, and start filming. Unit has a push-pull control on a three foot flexible cable to interupt and resume exposures.
Has never been used. Shortly after it was purchased My observatory was constructed so it was never needed.
Spectra sold these for $160. Asking $90 including shipping. T-ring and camera not included.