Shaped for right hands and built with cozy side grips, Signature Comfort M840 L helps you stay comfortable and in control, hour after hour. Feels like it was made just for you. The sculpted shape fits naturally in your hand. The thumb rest and extended rubber side grip give you confidence and control. It’s the perfect fit. Scroll line by line or fly through pages with SmartWheel—all with quiet clicks for a calm, focused workflow. Do more than you ever dreamed with the Logi Options+ App. Personalize your experience to make it work for you.