Unfortunately, it turns out that in use keeps the finger in the air (to avoid touching the surface) causes carpal tunnel syndrome! (In 30 years of computing, I never had any problems). Shame because it was lovely. FYI, since then I have a mouse "vertical" (Delux brand to 20) that eliminated my concerns (because the syndrome persisted after return to normal mice). Logitech Sorry, I love what you do but there is missed !!