The Gear Ring was designed by Ben Hopson and Glen Liberman from Kinekt Design. The ring features six micro-precision gears that turn in unison when the outer rims are spun (as can be seen in the video). It is made from high quality matte stainless steel.
It is currently available for purchase in four standard US ring sizes: 9, 10, 11, and 12. It can be purchased at kinektdesign.com.
Price: $165 USD, 120 Euros.
It has Lifetime warranty included. Free worldwide shipping and VAT/Duty not included.