Material and appearance: Made of thickened powder coated steel plate, it is sturdy and stable, and is not easy to deform, rust or wear out after long-term use. Smooth surface without scratches or cracks, decorated with raised patterns, stylish appearance and stable structure. Size and Structure: Accurate size, with an opening size of 50x50 centimeters, an overall frame size of 57x57 centimeters, and a height of 4 centimeters. There are two locking screws on the side to enhance the sealing with the square frame and improve the load-bearing capacity. Installation and use: Adopting bolt fixed installation method, equipped with thickened steel plate, sturdy square frame and two sealed locking screws, easy to install. The center has ventilation holes that serve both drainage and inspection functions, making it flexible to use. Applicable scenarios: Widely used in places such as ships, pump stations, and parking lots as drainage and inspection port accessories. Can be installed on the deck and inner floor of ships and vessels, capable of bearing a certain weight and reliably sealed.