The mega drop down slider works with the mega drop downs to locate light fixtures along the length of the mega drop down. Two 1/2"-13 × 1″ long hex head cap bolts both mount the fixture and lock the fixture onto the mega drop down. A nickel plated, spring steel 1" OD Belleville spring washer is provided to act as both a tensioning and locking washer. CNC machined from aircraft grade aluminum.