This is the same strap included with our Roll Bar Video Camera Mount (Part No. 2420). SCCA and many other organizations require a safety tether such as this to prevent a camera from coming loose and posing a threat to other drivers. We offer the strap separately to retrofit older mounts and other brands of mounts.
The red nylon strap measures 1" wide. Simply loop the free end around your mount and around your camera (through the handle or strap) and feed it through the metal buckle. The loop can be adjusted from 17" diameter down to just a few inches. Sold individually.