Neewer 15.4"/37cm Aluminum Alloy Extendable Double Travel Distance Track Dolly Rail Slider Video Stabilizer for Camcorder DSLR Camera Canon Nikon Sony,Load Capacity 17.7lbs/8kg This slider can move 74cm/30.8"(twice of its size),when mounted on tripod, and move 37cm/15.4" when put on ground.Note:Slider only;Camera, ballhead and Tripod are not included. Adopts 8 pieces of ball-bearings and rubber sliding belt to ensure smooth motion and minimize unwanted noises when recording. Top plate comes with 1/4" to 3/8" screw adapter for connection with ballhead or DSLR camera.Bottom Plate has 1/4"and 3/8" thread for connection with most tripod. Tightness adjustment for sliding belt and slider block by hex wrench. Orange screw knob for tightening down the slider block,High-precision aluminum alloy, strictly processed,? can load up to 17.7lbs/8kg. Note:Slider only and Camera, ballhead and Tripod are not included,when put on ground,it only moves within its normal size range.