Sold as 1 Each. | Nano USB provides strong 2.4 GHz wireless connection. Lightweight for travel at 65 g (2.29 oz). Button Life Left/right button - up to 8,000,000 clicks; Scroll click - up to 100,000 clicks. Power Requirement 1 AA battery. | Responsive and clear tracking with 1200 DPI resolution optical sensor. Battery life lasts up to 12 months(may vary based on usage). DPI 1200 DPI. OS Requirements Windows 10, Windows 8.1, Windows 8, Windows 8. WARNING: This product can expose you to chemicals including lead, which is known to the State of California to cause cancer, birth defects and/or other reproductive harm. For more information go to www.p65warnings.ca.gov. | Up to 8 million clicks for left and right buttons. Connection Type 2.4 GHz Wireless via Nano USB. Mouse Sensor Optical sensor. | Comfortable and functional in left or right hand. Mice Button 3 (left click, right click, scroll click). Hardware Requirements Supported PC with USB-A port.