It can be mounted to all clamp from Hejnar Photo and clamps from other manufacture equipped with slot on center. (Benro RRS) Slot must we wider than 0.207 inch. Please refer to your clamp specification in that matter.
Adapter let you switch setup orientation very quickly. It is very helpful in application where rotating clamp below is not possible, will require substantial amount of time or it is just simpler to keep clamp below in original position and have instant 90 degree rotation for your setup.