The button head socket screws are 100% Stainless Steel 18-8 (304) which offers a high level of chemical and corrosion resistance. The corrosion proof steel, makes them last much longer than screws made of common materials. The low profile of the socket button head makes a very clean looking, and offers a much larger contact surface. Thread Diameter 0.3125"; Head Diameter 0.547"; Head Height 0.166"; Screw Length 1.25"; Allen Hex Drive 0.187" (3/16"). Package Included: 10 PCS Button Head Socket Cap Screws 5/16-18 x 1-1/4". Button Head Socket Screws are great to have around for use in wood and wet environments. Size:5/16-18 x 1-1/4" (10 PCS) Product Specification Button socket cap screws feature a low profile, cylindrical head with a plain finish. The internal hexagonal drive hole, also known as a hex-socket drive, requires a hex socket wrench drive commonly called an Allen wrench, hex key or Allen key driver for quick and easy insertion. With its flush profile, button socket cap screws are ideally utilized in areas with little overhead or side clearance and suitable for light duty applications like machine assembly with removable parts and panels. Thread Diameter 0.3125" Head Diameter 0.547" Head Height 0.166" Screw Length 1.25" Allen Hex Drive 0.187" (3/16") High Quality Material 18-8 (304) Stainless Steel Package Included 10 x Button Head Socket Bolts/Screws