High quality white finish aluminum construction * Installs easily into most styles of sash windows * 8 Window sizes available: adjustable width from: 23-inch to 27-inch (23), 27-inch to 32-inch (27) and 33-inch to 38-inch (33) * Flap size 6-1/4-inch by 6-1/4-inch * 3 Window sizes available: adjustable width from: 23-inch to 27-inch (23) , 27-inch to 32-inch (27) and 33-inch to 38-inch (33)