Sold as 1 Each. The Adesso iMouse W3 has a waterproof design in which moisture or liquids cannot penetrate due to a sealed housing which protects the internal components from any damage. Don't worry about any accidental spills damaging your iMouse W3 because there are no cracks, gaps, or holes in this design. The optical sensor technology keeps the device precisely on point and lets you work on most glass, wood, marble and leather surfaces without a mouse pad. 1000 DPI Resolution makes this mouse ideal for precise control and navigation. Tracking method: Optical. Weight: 0.2 lbs. With 4 built-in magnets inside the scroll wheel, scrolling has never been smoother. Air-tight gaps are able to surround the scroll wheel and not effect scrolling functionality and liquids are unable to damage the scroll sensor. Buttons and controls: 4 buttons (right and left mouse button, magnetic scroll wheel and middle button). Antimicrobial material prevents the growth of harmful bacteria and germs and ca