The Foba ROGAO Adapter Trolley can be used to attach the Roof-Track cross rail to the Mega-Track trolleys designed for heavy-duty use.The top trolley glides on the master ceiling track, while the bottom trolley, which holds the equipment moves perpendicular to its own railThe Foba Ceiling Rail system provides optimum comfort and protection to the userIt also moves most of the equipment to the ceiling to give extra space for efficient workThe high-precision ball bearings present in this Mega-Track trolleys allow smooth gliding of appliances without noiseThis 5.5lb trolley, which is 12.2" long provides a proficient studio work