Button socket cap screws offer a wider bearing surface and high tensile strength but have a lower profile than a socket head cap screw. The socket head enables driving where there is not sufficient space for wrenches or sockets. The point at the threaded end of the socket cap screw is machined flat so it will fit into a drilled hole. 316 marine grade stainless steel is the choice for severe enviroments that require a high level of corrosion resistance. Type 316 stainless steel is the preferred material used in the marine enviroment and boating industry due to its resistance to pitting corrosion. 316 stainless steel has high resistance to corrosion from sea sealt water and industrial chemicals.