The Westcott 45" Halois a softbox that mounts like an umbrella onto many different brands of pack-type strobe heads. No speed ring is required. The Halo is mounted by using the hook and loop tape opening and to partially open the frame. The light inside Halo and shaft of the umbrella inserted into its receptacle. The Light may be moved anywhere along the shaft for harder or softer effects before being tightened down for use.