The period of protection of the self-drilling bolt in the project is its effective period. Once the bolt is corroded and broken, it must be re-protected. In seaports affected by groundwater and seawater, piers and water-impacted projects, due to construction difficulties and poor environment, the quality of the project must be guaranteed, that is, the service life of self-drilling bolts must be increased. In order to solve this problem, Sinorock® manufactured a double-coated rock bolt. Double-coated anchors use two protective measures on the surface: hot-dip zinc and epoxy paint. Hot-dip galvanized coating has dense combination, corrosion resistance and good toughness. Epoxy coating has high adhesion to steel and has excellent physical and chemical properties. Due to the wide temperature adaptability of this material, it can provide effective anchoring solutions for harsh demanding temperature conditions. It also has good toughness and wear resistance. The combination of these two methods can save the bolt for hundreds of years. Double-coated rock bolts are also suitable for roads and railway tunnels that are affected by groundwater, and undersea tunnels. Where there is water, there have double coating rock bolts.