This is a rail system I built the other day mainly to hold the Hasselblad 500mm lens I have access to. But also built with international measurements for fitting matte boxes, follow focus systems, monitor mounts etc. It´s all aluminium and fully ajustable, height and horizontal position of camera as well as horizontal position of the tripod plate. The lens holder is also ajustable, height and position. So the system is fully ajustable for different cameras and setups.