This is a very large and heavy duty ball head, the stiffest head ever tested by thecentercolumn.com
Very solid and smooth head, a bit over-the-top for the equipment I have now, and am selling as I have replaced with an RRS BH-55 head.
Modified by removing factory clamp and replacing with Wimberley C12. This uses the tongue-and-groove fitting of the original stem (that had to be filed down slightly to fit), plus 3 small anti-twist screws in addition to the main bolt.
The clamp, new, is £99 from Wex on it's own.
Spec for standard head with factory-fitted clamp from Feisol:
Ball Diameter 70mm / 2.75 inBase Diameter 90 mm / 3.54 inHeight 130 mm / 5.14 inchesMaximum Load Capacity 38.00 kg / 84.00 lbThread Size 3/8"Weight 0.94 kg / 2.07 lb