The heart of a video support system is the head. From the construction of the Sirui BCH video heads - forged aircraft grade aluminum alloy for maximum strength and long life - to the flexibility of its controls - up to 7 levels of drag for panning and tilting (plus 0 position) and up to 13 levels of counterbalance adjustment (position the camera at any angle without locking the head in place) - Sirui has designed and built a precision product that satisfies a videographer's needs. Smooth 3601 panning, 901 tilting, reliable results. That's what is demanded and provided. And it has the smaller features that add up to big advantages. Sirui calibrated Quick Release platform makes repeatable results easy. Their dual safety locking system lets you make adjustments safely and confidently. And the telescoping arms give you extra reach when you need it. The Sirui BCH-20 and BCH-30 have storage sockets for extra screws that can also be used to attach lights, microphones or other accessories. All Sirui video heads have two bubble levels - the conventional base bubble level for aligning the head on the tripod (it's illuminated) and the top bubble level that helps you horizontally align the camera. The Sirui BCH-10 and 20 come with an attached 75mm ball and the BCH-30 has a 100mm ball.