This puzzle is one of the most interesting turning of all gear puzzles, it really is a sight to behold, and the challenge is formidable but not too intense, on the other hand it is incredibly fun getting stumped over and over again by this one until you create an algorithm or two. A must have, I know they are currently sold out a lot of places but the manufacturer Mefferts recently did a reprint and had them on their website so expect to see them back in stock in a lot of places soon, pick one up wherever and however you can, you wont regret it.