Stainless Steel Star Drive Flat Head Machine Screws #4-40 Countersunk flat head with a star drive (6 lobe) Designed to prevent stripping during proper installation 18-8 Stainless steel is corrosion resistant and durable Suitable for freshwater environments Star drive flat head machine screws feature a flat head with an 82 degree undercut for a smooth and flush installation. The star drive reduces the chance of fastener stripping, allowing for a higher torque installation.