I use a variation, the Kodak Auto-Release. It clips onto generic cable releases and gives a hands-free self-timer so you don't shake the camera during long exposures by yanking the cable when on a flimsy tripod.
Some vintage cameras either don't come equipped with self-timer or the self-timer is finicky (or worse). I left it and a cable release at home for the Russian River shots, where I sorely needed it. Self-timer escapement on the Ikonta reluctantly clicked a few ticks per minute under pressure.
Also have a Prontor variation on the theme that you have to press to start but it lets you dial in a number of seconds that it holds the release down, up to 32 seconds.