The Arca Swiss Monoball Z1 dp (Double Pan) Ballhead builds on the success and popularity of their B-series ballheads. Z-Series ballheads are just as elegant and even more perfect. The size and weight of the ball heads have been significantly reduced. The ball and fastening are now assembled using a patented bayonet mount. Various accessories can thus be quickly mounted to adapt the tripod as required. The Z series can withstand an incredible 130 lb (59 kg) off-axis. This model is the dp version which features double panning. This means that besides for the standard pan base at the bottom of the head you also get a second panning mechanism below the camera mount. It can keep the camera perfectly vertical to the swinging plane and is ideal for perfect panoramic stitching. Ever since their introduction over forty years ago the Arca Swiss Monoballs have been at the forefront of quality and performance. Today their unique shape (an ellipse rather than a sphere) is still what separates them from all others. With other ballheads no matter how good the tension modulation you invariably will need to increase the tension control as you move the load away from the center. This is because gravity has a greater effect on gear when not perfectly level.