The NiSi Macro Focusing Rail is compatible with the Arca-Swiss mount and is equipped with an Arca-Swiss quick release plate New Quick Adjustment clamp with a push button New rail for easier adjustment New folding rotation knob Engraved graduated scale for precise adjustments Tripod mounting and A Four (removable) feet for direct use on tablessurfaces Length 200 mm with available area of 180mm For each rotation of the knob the deviation is 1mm Aluminium machined with high-precision numerical control machinery, 2-axis and 4 ways movement can be realised with two (2x) coupled NiSi NM-200s rails