Spigot is inserted into finish ring for smooth radius and can be trimmed to accommodate a variety of bulwark thickness. (Fasteners included). Bulwark thickness: 3". Cutout: 4-1/2" x 1-7/8". Opening dimension: 4-3/4" x 1-7/8". Flange dimension: 6-1/2" x 3-5/8".
