Glide Gear Adder 250 PRO Roller Bearing Video Track Slider Roller Bearing Sliding System 50 lb Load Capacity/ Solid Aluminum Rails 1/4-20 & 3/8Mounting Options On Feet And Middle Plate Bubble-Level on Sled/ Rail Ends/ Ball Head Not Included Bumpers/ 2 Sled Locks/ Protective Carry Bag