Features: Its mechanical properties are very used in axial parts Strong tensile strength,durable for long use and -oxidation very durable High hardness,bolt is hardened,to make it even stronger won't bend easily Its slightly domed with its hollow hexagonal footprint,you just need a hexagon screwdriver Specification: Material: Stainless Steel Color: Black Product Size(approx.): 5 cm Package Includes: 1 x Fixed Bolt Notes: 1. Due to the different monitor and light effect, the actual color of the item might be slightly different from the color showed on the pictures. Thank you! 2. Please allow 1-3cm measuring deviation due to manual measurement.