The round Leofoto DDM-55 bidirectional quick coupling with Arca-Swiss BPL-50 quick release plate is a loose quick coupling that can be turned on any 3/8-inch tripod screw. The DDM-55 has a screw knob for locking the quick-release plate and a second rotary knob for an adjustment in the longitudinal axis of the quick-release plate. Ideal for precise work on a panoramic head or a macro setup.