The APPH has a thumb screw that tightens the clamp onto any lightstand and some other surfaces. It has two red clips that lock the d-rings from the Pack onto the APPH and prevent it from falling off while moving around.
We recommend using the shoulder strap as an additional means of securing the Pack so that it doesn't rattle around as you move it from place to place during an event.
This simple clamp keeps the main weight of the Lumedyne at the bottom of your lightstand so it adds additional stability to the gear. It can be clamped to the center part of the stand or in many cases to the leg on the stand that is up hill or into the wind.