Amazon: Olympus
There are different cables, some are simple release cables, this is a pre-trigger which allows you to act as though the shutter is always quot;half-pressedquot; so you can manual focus your remote and not worry about your camera going to quot;sleepquot;.
The one shown is for Olympus, but they also make for Canon, and Nikon, make sure whichever one you order matches your camera system.