Rechargeable Optical Mousebuilt-In Durable Rechargeable Battery, It Can Be Easily Charged Using The Included Usb Cable Without Replacing The Battery. Just 2 Hours Charging, You Can Use It About 7-15 Days. Standby Time Is Very Long, Energy-Saving Features, Automatic Sleep Mode And Wake-Up Mode Are Installed To Save Energy. Turn Off The Mouse Led Light When Not In Use To Save Power.