The MS18 Macro Focusing Rail from Sirui is a precision linear motion lead screw focusing stage and rail, incorporating a camera platform with a rotating Arca-type quick release set. The rail has a capacity of 6.69" of travel distance, each full rotation of the crank providing 1.25mm of movement for precise camera positioning. The focusing knob has a crank handle that conveniently folds flat. The rail has a hollowed-out design to reduce weight, but it still maintains a robust 22 lb load capacity. The base of the rail features an Arca-type dovetail, making it easy to mount on compatible devices. It also has four removable, rubber-tipped feet for tabletop use.

The camera platform has a locking lever and incorporates an Arca-type quick release clamp that can be quickly rotated into four positions in 90° increments. The included quick release plate has traction pads to resist movement between the plate and camera body.