This is a rigid slow-motion control stalk for manual control of your mount's RA or Dec axis. The cable is 5" long (including the handle) and the end shaft has a 0.24" (6mm) bore. If your Antares, Celestron, Orion, Vixen or other mount has a knob or short stalk for slow motion control on either axis, then you can replace it with this control stalk for more convenient control of the slow motion function. Just remove the existing part (knob/short stalk), slide this longer stalk on to the slow motion shaft, tighten the locking screw (no tools required) and you are good to go. Sold individually or in pairs.