Cosmos Star Series Glossy Blue Color USB 2.4GHz Cordless Wireless Optical Mouse for Apple Macbook Dell Acer Sony HP Toshiba Laptop Desktop Computer Contoured shape ideal for left & right hand users Requires 2 x AAA batteries (Not included); Push the button which is on the bottom of the mouse to open the mouse battery cover that will find the battery compartment and the USB adapter. Effective operation distance is up to 10 meters With scrolling button, 2 level DPI switch USB receiver can be stored inside the mouse when not in use