i ordered this by mistake...i am NOT, and never HAVE been, a wireless guy...i have never used a wireless accessory in my life...i like everything cable connected...to me, it's just one more thing to go wrong in a long chain of things that can go wrong...i was just shopping for the "logitech" brand at a good price...i did not notice that this item was wireless...even when i unpacked it i was looking for the cable...i was not EVEN going to keep this thing...i do NOT like wireless PLUS i didn't have the little USB plug-in thing to make it work...so i went over to my laptop to start the return process...hey, in the picture it shows a little usb thing...where is it?....AH, it's in a handy niche in the battery compartment...neat...well, as long as i have it open, i may as well put a battery in and try it out before i return it...boy, was I surprised...this is the neatest item i've EVER "accidentally" bought...my wife had a wireless mouse and was constantly complaining about the batteries wearing out so quickly...looking around, i notice that this one has an on/off switch...she said her's hadn't had one...ok, i never looked--she MAY be wrong about that...anyway, i got this thing up and running and now you'd have to fight me to get me to give it up...whoa...i like it more each day...i do a ton of laptop work and i LOVE not having the extra mouse wire following me around...move it anywhere...no cable to worry about...just too neat...the price was right...refurbished?...eh, i guess...how much can go wrong with a trackball?...when i'm transporting the laptop, i can take the usb insert and put it ins handy-carry niche in the battery compartment...nothing to hit and get knocked off...nothing to lose...just be careful not to nudge open the battery door...i put a small piece of tape on the door to make sure it stays closed...the ball works like a dream...i've been using logitech 'balls since the early 90s, although my oldest one is a Microsoft with the round 6-pin connector...geez, it looks clunky...museum piece, anyone?...i'd NEVER use a regular ''mouse," though...this wireless works as good or better than the cabled unit...no skips or dead spots, which is what I was really afraid of...just great...i love it...