Polaris Dolly is designed for 1.5" – 2" speed rail/track, which you can extend to any length as per the shooting needsVarious camera and rig mounting options include Mitchell mount, 75mm, 100mm, optional Mitchell to 150mm bowl mount and cheese plate. ¼" -20 & ⅜" -16 threaded holes on each side and a 3/8" through hole in the middle allow mounting accessories such as LED lights or Monitors. Polaris Dolly allows you to mount your camera directly on the Dolly via ball head / fluid head, at floor level or tripods to achieve different levels of shots.