This project was an attempt to emulate the tactical grip-ring and lanyard attachment found on some LED flashlights.
The main issue was finding a binding knot which would hold securely enough on the smooth body of the flashlight, without being excessively bulky.
One of my first experiments was a 3×5 Turks Head, which looks nice and neat, and provided a nice grippy ring, but proved impossible to get tight enough to stay in place.
After a bit more research and experimentation, a Double Constrictor knot appeared to fit my needs very well, gripping very securely and having minimal bulk. Creating a couple of temporary loops in the working ends of the double constrictor made pulling it very tight a little bit easier.
When the neck lanyard is not required, it can easily be shortened using a chain sinnet. This then gives a handy fob for added grip, gear management, etc.
The flashlight shown in these photos is a Jetbeam RRT0.