The PMG-Duo 3-Wheel Pro Slider Carriage from ProMediaGear is a dual action slider carriage that features a straight and curved track in one slider body. The two tracks are CNC machined from a solid block of lightweight AL 6061-T6 aluminum. This slider can be used on a tabletop via the foldable legs on each side or attached to a tripod or tripods/light stands via standard threads in the middle or outside edges on both tracks. The sliding track consists of a clamp with 8 roller bearings inside 4 Delrin wheels (2 roller bearings per wheel), providing stability and low resistance for smooth motion. The carriage can be easily secured on the slider by simply tightening a knob. Loosening the knob allows you to remove the carriage from the slider. A second knob serves as a brake so the carriage won't move during transport.