Rubik's Clock LingAo — is a puzzle consisting of 9 dials, each of them has a front and a back side. The goal is that using gear mechanism to put all arrows of the dials to 12 hours with both the front and back sides. It is called the "Rubik's Clock", but the authorship belongs to Wiggs and Taylor inventors (presumably British).
Rubik's Clock LingAo are the best model of the puzzle, because have a perfect mechanism that rotates freely and lock-ups significantly less, as compared to the Clock from the brand Matchbox. Now the only problem with Clocks — are buttons that move freely after abundant lubrication, and sometimes can be set in the wrong position. Therefore, in Rubik's Clock LingAo only the internal gears is recommended to lubricate and better to keep the buttons dry.
Rubik's Clock — is the official event of the World Cube Association (WCA), so despite the low popularity of the puzzle among the common people, speedcubers train hard and are constantly update the world and national records in this event. By the way, the European champion Maarten Smit recommends for advanced cubers to use a hybrid based on the "Clock" LingAo with yellow buttons from Matchbox.
Unfortunately, the arrows in the standard version of the puzzle was drawn very inaccurate, and sometimes point at 2, 7, or 13 minutes instead of 0, 5 or 10. That's why we have decided to modify the Clock with such stickers for more comfortable recognition.