90% noise reduced Left/Right-click, Middle click 8Sound level comparison between Logitech M221 and Logitech M170. Left click dBA measured by an independent lab at 1m.
Sensor technology
Smooth optical tracking
DPI (Min/Max): 1000±
Buttons
Number of buttons: 3 (Left/Right-click, Middle click)
Scrolling
Line-by-line scrolling
Scroll Wheel: Yes, 2D, optical
Battery
Battery: 18 months 9Battery life may vary based on user and computing
Battery Details: 1 x AA (included)
Connectivity
Connection Type: 2.4 GHz USB wireless connection
Wireless range: 10 m 10Wireless range may vary based on user, environmental and computing conditions.