From Manufacturer
The Platyball Ergo Ball Head from Platypod has a different design than traditional ball heads. The Platyball Ergo features an inverted design, with the panning turntable at the top rather than the bottom.
The Platyball Ergo provides standard 360° swivel and 90° tilt adjustment. Instead of a conventional knob for locking this ball head movement, the Ergo has two buttons on the front that you can control with your index finger. One tightens and the other loosens the ball head. The front positioning of these two controls lets you easily use them even during a shot. You won't need to use a second hand. There is also a dial on the side for locking the pan rotation, and a button on top for locking and releasing the Arca-type clamp. The pan axis rotates a full 360°, and you can keep rotating it without end.
The Platyball Ergo features an Arca-type clamp on top and a 3/8"-16 thread on the bottom. A 3/8"-16 to 1/4"-20 bushing adapter is also included for the bottom thread. Additionally, a calibration/level disc is included that allows you to convert the top from an Arca interface to a 1/4"-20 screw to which you can attach your camera directly. The calibration/level disc has a 1/4"-20 screw on top and Arca-type dovetail on the bottom. It also has a 3/8"-16 thread on the bottom. The purpose of the 3/8"-16 thread is for mounting the Ergo on the various optional Platypod plates that are available sold separately.