Looks like a RRS BH-55 to me
putting the ball head on a levelling base for panos is a bit of a waste
Absolutely, in fact I regard a levelling base almost essential for a gimbal head and for a 'nodal' rail saves the frustration of messing about trying to get it all level by adjusting the legs, not a great deal of point with a ball head though, level off using the ball, mount a rotating adapter on top and away you go... there were a couple of threads here recently on this topic. Saves a lot of money too...Of my 4 series 5 Gitzos, 3 have levelling bases… no brainer:
one for each of my 2 gimbals and the panorama head as well.