Used to support the 12x4 system by spanning two threaded rod drops that are 24in apart. Ideal for supporting trapeze bracket from 24in wide ladder rack or 24in wide cable tray. Can be installed from above or below. Bracket is secured to each threaded rod with two nuts. The pre-assembled slide clamps enable fast assembly to channel. Use 7/16in nut driver on slide clamps For 1/2in threaded rod.