If you go to the Spot-hogg website, there is a video on the Whammy. According to the info, the cable is connected to the up traveling cable. As you draw the bow back all tension on the cable is removed and the shock of the shot causes the release to fall away(I guess). The act of the up-cable moving back to it's orginal position, resets the rest. I thought the setup was simple. Just install the rest, pull the cable tight and go. No timing required. There was a thread on AT.com about the rest. It's on my list of rests to look at for my 07 Ally once I get back home. The slow motion video is great.