The Sirui G-20 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 head tilts 90° for portrait orientation, and the quick-release plate features two pop-up pins that prevent camera twist when it"s tilted 90°. There"s also a video pin on the plate to keep camcorders from twisting.The ball locking of the G-20 head is extremely strong thanks to the double-bevel locking system, which helps yield a high load capacity of 44 lb. 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 & stability.The three separate controls allow a photographer to exercise extremely fine control over the orientation of the camera, whether it"s a DSLR, 35mm, medium-format camera, or even a camcorder. Pan, for instance, can be adjusted while the tilt stays locked, enabling precise movement that"s measurable - there are degree markers at the panning base for panoramic photography.The G-20 is CNC-machined from an aircraft-grade aluminum alloy and anodized with an oxidation treatment that ensures a durable, high-quality finish. Arca-style quick-release clamp with secondary safety lock Independent friction-control knob allows the operator to adjust the resistance of the ball"s movement Quick-release plate is aluminum alloy with a rubberized surface Stainless steel camera screw