The compact professional SLIK PBH-535AC is an Arca-type compatible ball head designed for photographers on the go. The 535AC features a slim profile, weighs 13.4 ounces, includes a universal Arca-type quick release platform so you can use just about any Arca style quick release plate, L-bracket, and is even compatible with backpack "Clip" systems. It includes 3 control knobs to control the functions of the head: 1) Large Lock/Release Knob to control framing 2) Tension knob to control the friction of the ball movement 3) Pan Knob controls 360° panning left and right independent of the ball movement. The head includes a single U-notch for greater flexibility of camera position. You can point the camera straight up or down and shoot horizontal and vertical frames. The 535AC has a load capacity of 11 lbs and is capable of supporting full-sized professional cameras and lenses. SPECIFICATIONS Max Load 11 lbs Height 4” Weight 13.4 oz Material Aluminum Arca-Compatible - yes