I use the trackball for years after I as an intensive PC-workers had previously repeated the "mouse arm" (problems such as the tennis elbow). When trackball are hand and arm relaxed on the table and only the thumb moves the cursor ball. So far I used the wired previous, which has given up the ghost after mechanically years. At the same time I have several standard mice exchange among employees due to wear. On the slightly modified form of the new trackball version - and wirelessly - I had acclimated me for a day. If the machine keeps exactly as long as the previous one, justified the over standard mice higher purchase price.
