I took the X7 XL-750BF in return, the scroll died, I cleaned it several times, but it seems the time has come. I was looking for something "more interesting" I came across this instance, there are disadvantages, you can't get away from them, the most important thing is the whistle, the mouse whistles until I can figure out why, but it's terribly annoying. It’s not bad in the hand, the right flattened side is almost familiar (I’m right-handed). As I use it, I’ll supplement the review.