(From company literature) Really Right Stuff BH-55 Pro Ball Head.
Features:
Ergonomic design gives superior handling and unsurpassed reliability.
Lowest profile in its class.
Large main locking knob incorporates stainless steel ballbearings for a lifetime of silky smooth control.
Dual drop-notches allow maximum flexibility for positioning the camera.
Micrometer tension adjustment is repeatable and absolutely reliable.
Precision panning base is finely laser-engraved at 2.5 degrees intervals and features our unique drum & brake design for effortless locking.
All components are of the finest Really Right Stuff quality, machined from solid aircraft aluminum or stainless steel for maximum durability and minimum weight.
Comes with screw knob clamp for tried and true clamping strength.
Comes packed in its own OP/TECH neoprene protective draw-string pouch. Use the pouch to cover and protect the ballhead when mounted to the tripod, for carrying the ballhead in your carry-on luggage when traveling, or when the ballhead & tripod are strapped to a photo backpack.