Wireless Battery Free Optical Mouse Manufacturer: A-FOUR TECH CO., LTD. Use of the equipment: For PC’s Mouse Equipment category: Wireless Battery Free Optical Mouse Mode of operation: Simmplex Frequency / Frequency range: 121 ~ 128KHz Maximum transmitter output power: SECIFICATION 2.5 mW Number of channels and channel separation: Scan frequency to lock a working point for Wireless Battery Free Mouse . Working frequency of Every Mouse maybe be different , working point from 121 KHz to 128KHz.