Fixed Length Extension Column for use with Peerless AV Display Mounts, Projector Mounts, and Ceiling Plate Accessories. 1-1/2" to 11.5 NPT threaded on both ends. Notched for use with screw to provide safety and security. EXT model extension column lengths measure 1" (25mm) longer than stated drop to provide finished drop length for various mounts; Lightweight aluminum construction for ease of installation and lower freight cost; Cable management access provided at one end of column.