The Lowel SC-10 Large Space-Clamp locks onto posts, beams and objects with spans from 25" to 8' to support one or more lights, flags, etc. The bar, made of high-strength aluminum aircraft alloy, interlocks without tools to adjust to various widths.
It can also reverse and jack out to clamp between objects (not recommended with two or more bars interlocked). The Stud Bracket locks onto any part of the arm. The Space Clamp also accepts the Tota-tilter and the Lobo for a variety of accessories.