As a right-handed, which I have a lot of professional graphics applications as well as spreadsheets and therefore used the 10-button keypad my habit for years to use the mouse with the left hand. Each left-hander knows the problem: there is no reasonable mice for the Left Hand. With the Razor Ouroboros I am now become finally found it. The ergonomics are very good for a symmetrical rationale in mouse. Especially because you can adjust the mouse ferfekt with attachments and other settings. For me, worth every euro.