Batteries purchase

A4Tech FB35 2.4G Bluetooth Mouse Features: Bluetooth 4.0/3.0/2.4G: FB35 comes with dual mode — Bluetooth mode and 2.4GHz Wireless mode, which bring quick response, precise movement, stable connection & smoother tracking. Switch up to 4 Devices: 4 Devices can be connected at the same time. It realizes free switches between 3 devices only by one click. 2 Thumb Side Buttons: The side buttons are preset as backward and forward functions, and can be customized with software. 2000 DPI 4-Level Adjustable: Adjustable resolution 800-1000-1600-2000 DPI. 16-in-One: 16 gestures to perform selectable hotkey commands. On/Off Power Switch: Switch button on the back make this wireless mouse to perfect on-the-go companion. Online prices, specifications, description and images generally match actual, but may vary and are subject to change without notice. Vmart cannot be held liable for errors or omissions.Please verify the specifications at the time of purchase. No claim whatsoever would be accepted in case of specification error/mismatch, once the product is sold. SPECIFICATIONS: Sensor: Optical Distance: 5~10 m Report Rate: 125 Hz DPI: 800-1000-1600-2000 Buttons: 6 Style: Right-Handed Fit Receiver: Nano Receiver Demension: 105 x 70 x 42 (L*W*Hmm) Weight: 74 g (Batteries not included) System: Windows 7 / 8 / 8.1 /