These boat hatches are seriously sturdy and perfect for all kinds of marine applications! Each hatch has a 4-inch inner diameter with a 5.4-inch outer diameter, and you'll need to cut a 4.25-inch opening for installation. Made from high-quality ABS plastic that's built to last - we're talking UV resistant, corrosion proof, and it won't crack or fade even after years in the sun. The non-slip surface gives you good traction even when wet, and the clear detachable cover lets you easily check what's inside without opening the whole thing. Installation is straightforward with the included stainless steel screws - just make sure your cutting is precise for that perfect fit. I've used these on my kayak and fishing boat, and they've held up beautifully against saltwater and weather. The pack comes with two hatches and twelve screws, which is perfect if you need multiple access points. Whether you're installing them on boats, RVs, or any outdoor equipment that needs inspection access, these hatches provide reliable protection while staying easy to open when you need them. The black color looks professional and doesn't show dirt easily, which is always a plus for marine gear!