Specification:

Color:  blue
Sensor technology: advanced optical tracking technology
Optical resolution: 1000dpi
Number of buttons: 3
Roller: Yes
Battery type: 1 AA battery (not included)
Wireless operation distance: about 10 meters
Wireless technology: Advanced 2.4 GHz wireless connection technology
Interface: USB receiver
Supported operating systems: for Windows Vista,Windows 7,Windows 8,Windows 10, for MAC OS X 10.5 or later, for Chrome OS
Package size: 105mm*70mm*40mm/4.13*2.75*1.57''

Note:

Please allow 1-3mm differs due to manual measurement.

Due to the different display and different light, the picture may not
show the actual color of the item. Thanks for your understanding.