Lenovo 500 Wireless Mouse, Silver (GX30J39644) Size designed to balance ergonomics with comfort and portability;Multiple CMF finishes1000 dpi 2.4GHz wireless technology, Micro USB receiver 3 Buttons: (1) Left click, (2) Right click, (3) Click wheel , Standard Scroll Wheel Buttons (L/R) life: 3 million clicks, Multi-CFM: 4 CMFs