This Fotolux 4-ways Macro Focusing Slide Rail can be adjusted in four directions: forward, backward, left and right. It can adjust the camera distance easily (as macro photography is shot in a very short depth of field, the focus can now be precise).24mm height difference between camera mounting plate to first rail, and 24mm from first rail to second rail.To be used with a tripod for stability (thread holes on the bottom; tripod ready)The rail positioning adopts adjustable locking knobConstantly adjust the distance to the object you want to photographThere is a 1/4 inch standard screw that fits most of professional DSLRRail allows 5cm moving leftward/rightward, and 10cm moving forward/backwardThe rail adopts durable metal slider, and a geared drive system which enhances accuracySpeed of adjustment of the rail greatly with two precise double scales, and allows precise distance modificationsMax Range: 100mmLength: 160 x 160 x 85 mm( L x W x H )Package Includes1x Fotolux 4-way Macro Focusing Rail Slider