The gitzo gs3750dqd series 3 qd panoramic disk is a useful accessory that can be attached on top of a gitzo systematic levelling base or on top of or underneath another head that doesnt have its own independent panning axis the 38 thread and the included 38 screw adapter allows the disc to be attached to various tripods head and other supports the panoramic disk comes with an arca style quick release plate gs5370d