From Manufacturer
The Manfrotto 502AH Pro Video Head with Flat Base is an affordable yet remarkably fully featured professional head that represents an advance over the popular 501HDV, with sturdier construction and featuring Manfrotto's patented bridging technology (inherited from the 509 and 504 heads). This head is designed for executing cinematic moves with compact camcorders and DSLR cameras. The 502AH comes in two versions—the "AH" flat base version with a 3/8"-16 mounting hole such as this one, and the "A" ball base version, which is separately available.
The weight capacity is 22 lb and the counterbalance supports 8.8 lb. The balance plate's 3.27" range allows you to correct for uneven payloads due to matte boxes or DSLR rig configurations.
The bridging technology ensures that the pan friction control is intuitive and easy to set but is also protected against knocks. There are independent locks for pan and tilt, and drag for both is selectable in a continuous range from zero to the maximum level. This allows you to operate the head in a confident, smooth manner using the included pan bar.