Upgrade to smarter scrolling, better comfort, and more productivity. The Signature M650 features SmartWheel scrolling that delivers precision or speed the moment you need it. SMARTWHEEL SCROLLING: Make scrolling work for you with Logitech SmartWheel. Get line-by-line precision when you need to focus on the details, and scroll super fast when you just want to breeze through lengthy pages. Automatically switch modes with the flick of your finger.