Use this 8-inch extender to lower the projector or camera by 8 inches. It includes a 1/4 in x 20 threaded screw hole in one end and a 1/4 in x 20 threaded screw on the other.  1 or 2 of these rods are included with all ALZO drop ceiling projector mounts. Specifications Dimensions: length: 8.5 in.(incl. end screw); diameter: .625 in / 5/8 inch) Weight: 0.7 pounds MAXIMUM AXIAL LOAD 40 Kilos (88 Lbs)