From The Light Source comes the MSASB – which is a Mega-Sidearm Slider that comes in black. A Mega-Sidearm Slider can be purchased separately to fasten directly to the Mega-Sidearm. The slider is a 1″2″3″ aluminum block, CNC machined to fit over the Mega-Sidearm. There are two drilled and tapped 1/2″ holes. One hole is for fastening to the light fixture, and the other hole is for locking the position of the slider.