In cinematography, a jib is any boom device used to mount a camera on one end, and a counterweight with camera controls on the other. In principle, it operates like a see-saw, with the balance point located closer to the counterweight, which allows the end of the arm with the camera to move through an extended arc. Typically a jib permits the camera to be moved vertically, horizontally, or a combination of the two. A small jib can be mounted on a tripod, but many larger, purpose-built jibs have their own support stands, often on wheels. Modern jibs are normally modular and can be assembled in various lengths.