Adjustable shaft: overall mount length from 9.375-Inch (238.1mm) to 13.625-Inch (346.1mm). Shaft locks tightly and is indexed to prevent rotation. * Use the Tri-Foot Base [4-Inch (101.6mm) outside diameter with three 0.265-Inch (6.7mm) holes on a 3.25-Inch (82.5mm) bolt circle] for solid surfaces, or the T-Bar Clip for drop ceiling rails * Full range of motion: 210 degreesTilt, 360 degreesTurn & 360 degreesRotation * 1/4-20 mounting stud with lockring * Knob and tamper-resistant set-screw adjusting options included * Telescopes from 9.375 in. (238.1mm) to 13.625 in. (346.1mm) overall length. * Telescoping section indexed to prevent spinning. * Both Tri-Foot Wall-Ceiling base and T-Bar Clip included. * 883-T is knob adjustment for ease of repositioning camera, without any tools.