Feature:1. Heavy Duty Frame: The overall frame of the push out porthole window is manufactured from heavy duty aluminium alloy and the anodised surface is polished to a smooth finish for long lasting use in outdoor environments.2. Fine Workmanship: The 6mm thick anthracite grey acrylic glass ensures overall sturdiness and the support bars are manufactured from 316 stainless steel to ensure that the skylight is rust resistant throughout.3. Waterproof and Anti UV: The waterproof rubber ring provides a complete waterproof seal and dampens vibrations, filtering out UV rays while ensuring light can enter the compartment, enhancing the brightness of the cabin, and can also be used as a ventilator window.4. 90 Opening Angle: Marine portlight window with switch lock handle and fixed support rod, supports 090 degree angle opening, you can enjoy the scenery along the way.5. Wide Application: Suitable for 15mm thickness installation, can be used for boats, yachts, ships, and RVs, can be used for sunroof, escape window, storage compartment, roof, or anywhere.Specification:Item Type: Boat Porthole WindowMaterial: Aluminium alloy + Nylon + Acrylic glass + 316 Stainless SteelWindow External Size: Approx. 520x515mm / 20.47x20.28inOpening Hole Size: Approx. 450x450mm / 17.72x17.72inMaximum Light Transmission Size: Approx. 440x440mm/17.32x17.32inSuitable For Installation Thickness: 15mm/0.59in, or any thicknessPush Out Opening Angle: 0-90 degreesApplication: for Boat/Yacht/Nautical/RV.Package List:1 xBoat Porthole WindowNote:1. Installation is slightly difficult, it is recommended to look for professional engineers to assist in the installation to get the best shopping experience. 2. Please pay attention to avoid collision when disassembling and assembling. 3. Please measure the size before purchase to make sure it is what you need.4. Please allow slight error due to manual measurement.