The CMS Speed-Connect Adjustable Extension Columns lower projector to desired height. Features: - Provides height adjustment in 1" increments. - Knotched design for adjustment without disassembly. - Flow-through cable management with cable exit port. - Includes set screw for add stability. - Consists of 1.5" NPT column, threaded on both ends. - Use in combination with any Chief 1.5" NPT ceiling plate or other accessory.