Altman 510-HD Heavy Duty Iron Pipe C-Clamp

In stage lighting, a c-clamp, also referred to as a pipe clamp, is used to attach a larger piece of hardware, such as a lighting fixture to a pipe, batten, or tubular trussing. C-clamps function by affixing a bolt (the "shaft bolt") to the hardware they are to hold in place, such as through the yoke of a lighting instrument, and securely fastening this bolt to the clamp shaft. The open end of the clamp is then placed over the pipe batten, and a bolt (the "clamp bolt") is tightened to secure the c-clamp.

To aide in your lighting focus Altman Lighting c-clamps also employ a pan screw (also known as a "grub bolt"), which when loosened will allow the clamp shaft to rotate, and therefore the fixture, to be rotated 360 degrees while maintaining a secure connection to the pipe batten.