Rechargeable: Built-in rechargeable battery, no need change battery. Special soundless design for the right and left buttons, won’t disturb others. Colorful Light: 7 different color changes randomly while in use, offering soothing lighting, creating cool and fancy atmosphere for work and play. Energy Saving: The mouse will be in sleep mode in 8 mins of inactivity. And the LED light can be turned off by the bottom light switch.