Chief cms012018 cmso12018 cms 012018 12 18 304 457cm speed connect adjustable extension column cms speed connect adjustable extension columns can be used with any 1 12 npt accessory to lower projector to desired height provides up to 2 range of height adjustment in 1 increments depending on model 6 to 12 lengths includes set screw for added rigidity notched adjustment design for length changes without disassembly