The Sirui K-40II Ball Head are designed and built to the highest standards. The tolerance between the ball and the bearing on SIRUI heads is a max. 0. 01 mm. The superior quality is achieved by high-end CNC milling and high quality surface finish. The base can be smoothly rotated by 360 Degree , thus panoramic shots are a breeze. With the three spirit levels the head can be perfectly aligned. The clamping device is compatible with the Arca-Swiss system, enabling the use of various quick-release plates. The safety lock system prevents accidental slippage of the quick release plate. The precise control of the knobs allows very smooth and effective locking and unlocking of the individual components. The knob for the friction of the ball can be limited in the KII series included is a limit scale for easy reference.