For last few weeks I was creating linear motion lead screw focusing or micro rail. The bottom rail include Arca Swiss compatible dovetail that works with Arca Swiss type clamp while the slider is equipped with quick release clamp. Clamp can be oriented in 4 positional using 2 sides holes. Camera to subject distance can be adjusted in fine increments . Lead screw delivers 1.06 mm of travel per full revolution. Fast positioning can be done by pressing slider release lever and slide the slider on top of the rail. This rail is design to work with small and light DSLR. It is not recommended for heave cameras with long lenses. It does not include any lock down mechanism for slider. Works very nice as a nodal slide.