... are high-quality zinc alloy material, to ensure the qualitystability.(3)Zinc rod through the lathe precision machining, cutting, drilling, ... thread(4)Through the multi-channel polishing process, so that the surface bright, if anyscratches and defects have to be re-polished. ... oblique tongue, so as to ensure that in case of emergency escape rapidly from the indoors.If you have any question, please ...