Feature: 1. Corrosion Resistant: The overall frame is made of heavy aluminum alloy, and anodized surfaces are polished for a matte texture and corrosion resistance, will not be eroded even in harsh offshore or outdoor environments. 2. Tempered Glass: The skylight glass part is made of 6mm thickness smoke gray tempered glass which filters out ultraviolet rays while ensuring that light can enter the cabin, improving the brightness of the cabin, and can also be used for ventilation Windows. 3. Waterproof: The porthole frame is equipped with waterproof rubber rings to provide complete sealing and waterproof performance and shock absorption performance when the window is closed. 4. Push Out Opening: The porthole can be opened at will in the range of 0‑90 degrees, and equipped with 316 stainless steel support rod and hinge, providing fixed support at any Angle. Good for boat, yacht, ship, and RV. 5. Multipurpose: Portholes can be used for sunroof, escape window, storage compartment, roof, or any location modification and retrofitting projects, with 21x25 inch appearance size, 18.4x22.4 inchxR45 mounting hole size, 1‑2 inch thickness installation. Specification: Item Type: Boat PortholeMaterial: Aluminum alloy + tempered glass +ABS+ rubber +316 stainless steel Switching Mode: Push outward, with stainless steel support rod and locking handle Maximum Opening Angle: 90 degrees Window Dimensions: Approx. 525 x 625mm / 21 x 25 inches Installation Hole Size: Approx. 460x 560mm x R45 / 18.4 x 22.4in xR45(please allow 3mm error) Applicable Installation Thickness: Approx. 25-50mm/1-2 inches Application: for Boat/Yacht/Nautical/RV, can be used for your boat yacht RV retrofitting and other projects, to provide a solution for your leaking, broken and unsatisfactory Windows. Package List: 1 x Aluminum Alloy Boat Porthole Note: 1. The installation is slightly more difficult, it is recommended to find professional engineers to assist the installation to obtain the best shopping experience. 2. We will provide high hardness and all round protection of the packaging, the goods delivered to your hands is a new and non damaged state, please pay attention to avoid collision when disassembling 3. Please measure the size before purchase to make sure it is what you need