These hexagon head combination bolts are made of high-strength alloy steel with hardness grade **10.9**, featuring excellent tensile strength, shear resistance and anti-loosening performance under long-term vibration. Surface treated with blue white zinc plating, they provide good anti-rust and anti-corrosion properties for general industrial and outdoor assembly environments. Adopting an integrated 3-piece design — hex head bolt + flat washer + spring washer — the assembled structure prevents washers from losing or misplacing, greatly simplifying installation and improving work efficiency. Standard thread precision and stable clamping force make them widely used in mechanical equipment, automotive parts, electrical cabinets, steel structures and various fastening scenarios requiring convenient and reliable assembly. Each product is strictly inspected for dimensional accuracy and mechanical performance. Complete specifications are available with factory direct supply, providing economical and durable high-strength combination fastening solutions.