I want to add that I own and have used forever an Arca Swiss B1 head and still enjoy it. Their stuff is well designed and well made. However, they are not inclined to make camera specific plates and brackets. And so their stuff was never widely supported. Then RRS started using the original Arca Swiss Plate and clamp design and marketed custom brackets. RRS efforts, along with Kirk enterprises, made the original Arca Swiss design into a standard. Then Arca Swiss decides to change their plate and clamp design throwing the whole Arca Swiss compatible statement into disarray. Hence, I studiously avoid supporting the NEW Arca Swiss design. I might end up with a P0 and will buy it without a clamp and add a RRS clamp to it.