We used LED lights on the bridge of the ship, joint fittings to attach them. The mounting hole was small for 8 mm because it was small, but the installation went well. Because it was rusted if it was not stainless steel for the ship, I was looking for it. The upper part of the convex type was the best if there was a slightly wider thing, but there was no problem with the installation. I searched for a home center etc, but there were iron objects, but there was no stainless steel object. It was saved.