Move content between 3 computers. Download Logitech Flow and move text, images and files seamlessly between devices. Darkfield (tm) High Precision tracking. Enjoy flawless control on virtually any surface, even glass. (4mm min. thickness) Fast recharge. Power up for a full day of usage in just 3 minutes. Holds power up to 70 days on a full charge. Hyper-fast scrolling. Speed adaptive scroll wheel switches from click-to-click to ultra-fast scrolling. Experience side-to-side scrolling with a simple thumb stroke. Comfortable shape. Carefully crafted to support hand and wrist in a comfortable natural.