I bought in March 2013 vertical mouse Anker I had noted with 2 stars only because of the unbearable noise caused by each click. Anker took into account my opinion and sent me a new mouse that replaces the first acquired model. On this new version all identified problems are corrected: the mouse is more ergonomic and thus takes firmer hold, the buttons have become "normal", and, best of all, the design is further enhanced with a pretty blue light on the side. The mouse is less plastic with a softer coating. Besides, of course, the essential: the end of pain problems through the verticality of the mouse. In short, an amazing product, an unbeatable value for money (especially when you see the price of certain vertical mouse) and a customer service incredibly attentive to customers. Experience definitely this new type of mouse without breaking the bank!