Scubapro Hydros Accessory Bungees are smaller than they look, but the Medium size works well for securing my action camera floatie handgrip in place. To set them up, you loop the bungee back through itself to attach to the d-ring fixation point. The center piece then slides down to clamp the accessory.
While they perform great with the grippy, foamy action camera handle, they may be less secure on heavier gear with a slick surface—like my dive light. For that setup, I’d recommend adding a second attachment point on the BCD (for example, using the metal d-rings with a snap hook on a longer lanyard) to help ensure the light doesn’t end up on the ocean floor.