You are a wave rider or hydrofoil rider and you use a rope harness, instead of the typical steel spreader bar (for instance: Engine, Da Kine, Ion, Mystic, ...).
Pascal customized his harness and replaced the typical stainless steel buckle with a rope. Pascal explains how to set up a friction ring to prevent wear of the rope and the chicken loop tube and help the chicken loop slide even better on the rope. As a reminder, without this friction ring, the harness rope could get damaged and it could also end up cutting the chicken loop tube. The friction ring is an excellent option to avoid wear.
Here is the friction ring that Pascal uses: