Attwood"s anti-glare lights are a great improvement ? they focus light at the horizon and above, not in the pilot"s eyes. The bottom aperture reduces glare at 7.5 Degree below horizontal. * Above horizontal, the continuous arc of light makes the boat more visible to taller craft * The patented articulating head adjusts from 15 Degree forward to 15 Degree aft. Just align to the horizon and tighten the adjustment screw! * Simplifies inventory because one light fits most angles and installations * Simplifies installation, too, because the universal locking collar pole fits 95% of existing bases ? Attwood models as well as competitive bases such as perko brand