SeaTeak Louvered Insert 16"H Insert requires 15"Hx8-1/8"W cutout 7-1/2"H Insert requires 6-1/2"Hx8-1/2"W cutout 6-3/8" Insert requires 5-3/8"Hx10-3/16"W cutout 9-3/8" Insert requires 8-3/8"Hx16-3/4"W cutout