Phillips Oval Head Machine Screws 316 Stainless Steel - 1/4"-20 Countersunk head with a raised domed top Used to secure materials that may be tampered with 316 Stainless steel is corrosion and rust resistant These screws are ideal for saltwater moisture environments Phillips oval head machine screws feature a raised decorative head, with a countersunk bottom and a round top. Phillips head machine screws are often used with nuts as well as driven into tapped holes.