I lost two cable releases last week on the same excursion - inexplicably, both my mechanical release and the silly little plastic thing for my DSLR escaped me. I'll never understand how that happened, but anyway...
I've bought two new mechanical releases for use with my medium format cameras. The first one had an extruding wire, dangling about an inch from the thread, bought a second one from a different online store and the same thing:
The item description clearly stated they were universal mechanical releases, but I'm unable to attach them to my Hasselblad or Pentax 67.
With the one I lost, the wire was only visible upon pressing the button - popping out about a couple of millimetres.