Robust Construction: The overall frame of the porthole is made of heavy duty aluminum alloy, and the anodized surface is polished to smooth, ensuring rust resistance and oxidation resistance for a long time. Acrylic Glass: The light transmitting part of the window is made of acrylic glass with a thickness of 10mm, which can filter out ultraviolet rays and ensure that light can enter, improving the brightness of the cabin. Waterproof Design: The whole frame of the window is equipped with rubber ring, and the sealing ring can provide complete sealing waterproof performance and shock absorption effect. Flexible Opening: Porthole adopts internal opening design, double lock fixed, used for 0-180 degree angle opening, and can be used for porthole, skylight, ventilation window, storage compartment, or any position. Widely Use: 347x 171mm open hole installation comes with aluminum alloy fixing clip frame, suitable for 5-25mm thick walls, ideal for boats, yachts, ships, and RVs, providing a solution for your leaking, broken windows.