The Sirui K-20X II Ball Head unique locking mechanism for guaranteed precision and safety. Separate control knobs for panning and locking. Friction knob is conveniently located on the main locking knob. 3 bubble levels allow precise horizontal leveling for critical shooting situations. Arca-compatible SIRUI Quick Release Plate TY-50X, rubber non-slip surface and 1/4 bolt with folding D Ring for easy attachment to your camera.