The Allied Bolt Extension Bolt (vendor part 2070, Millennium part 528206) is a 7 in bolt for 5/8 in-11 threads that lets crews add a second cable or strand at the same elevation on an existing suspension bolt without redrilling the pole. Its 4 in internally threaded section joins the existing bolt while the 3 in external thread accepts a new suspension clamp. Hot-dip galvanized to ASTM F2329, it holds up under continuous outdoor load on aerial cable runs. Millennium stocks the longer 11 in extension bolt and matching suspension clamps for the same expansion jobs.