Logitech MX Master Wireless Mouse (Certified Refurbished) Certified Refurbished product is tested and certified to look and work like new. The refurbishing process includes functionality testing, basic cleaning, inspection, and repackaging. The product ships with all relevant accessories, a minimum 90-day warranty, and may arrive in a generic box. Only select sellers who maintain a high performance bar may offer Certified Refurbished products on Amazon.com Smart speed-adaptive scroll wheel: Auto shift from click-to-click to hyper-fast scrolling Unique thumb wheel: For horizontal navigation and advanced gestures Easy connections for multiple computers: Use with up to three Windows or Mac computers via included Unifying receiver or Bluetooth Smart wireless technology. Easy switching between computers with the touch of the button Tracks virtually anywhere - even on glass: The Dark field Laser sensor tracks flawlessly even on glass and high-gloss surfaces ( 4mm minimum thickness.)