The Sirui G-10X Ball Head is an extremely sturdy head with separate control knobs for pan, tilt, and tension, plus an Arca-style clamp for the included quick-release plate. The ball locks down extremely tightly thanks to the double-bevel locking system which allows support of cameras up to 39.6 lb and safe 90° tilting for portrait orientation. The quick-release clamp features a secondary release button that prevents any inadvertent disengagement of the camera/plate from the clamp, thereby adding to the head's overall security and stability.
eBay