PULUZ Macro Focusing Rail Slider Close-up Shooting Tripod Head Quick Release Plate Holder 1. Precision CNC machined from solid aircraft Aluminum, light weight. 2. High level hard anodized finish makes the surface durable and not easy to wear. 3. The rail is driven by a knob-controlled worm gear and index scales, in millimeters, are printed on both sides of the rail for consistency. 4. Sliding speed adjustable, you can slide slowly or you can go fast. Screw-knob with CNC cutting texture, for better gripping. 5. Helping to achieve exacting camera-to-subject distance, the Macro Focusing Rail is a focusing stage offering fine- tuned control across a 115mm adjustment range. 6. Standard dovetail groove, compatible with ARCA, RRS clamps. Compact and super lightweight, easy carrying. It has longest range thanks for the compact QR plate design. 7. Cameras can be mounted on top of the rail via the integrated 14 inch screw, which uses a 48mm-diameter thumbwheel to secure cameras in place. 214mm overall length (including adjustment knob).