The Cup Square Bolt with Anti-Theft Nut and Spacer is a high-security fastening solution designed for applications requiring tamper resistance and structural integrity. The bolt features a domed round head with a square neck that prevents rotation when installed into a pre-punched square hole. Manufactured from high-strength carbon steel or stainless steel (Grades 4.6, 8.8, A2, or A4), it ensures durability and resistance to corrosion. The accompanying anti-theft nut—such as a shear nut, tri-groove nut, or pin-hex nut—is designed to deter unauthorized removal, requiring a specialized tool or shearing off its hex portion once fully tightened. The nut is typically zinc-plated, hot-dip galvanized, or finished with a corrosion-resistant coating like Geomet. The spacer, fabricated from metal or engineered polymer, is used to maintain consistent spacing and load distribution between connected components. This assembly is commonly used in public infrastructure, road signage, outdoor enclosures, fencing, and industrial machinery where security and vibration resistance are critical. It meets relevant ISO and DIN standards and is available in various sizes, finishes, and configurations to suit project-specific requirements.