Features: 1 Adopt the 2.4G RF wireless transmission technology and link distance is long enough for mega-size classroom. 2 Use rechargeable battery; environment-friendly convenient and economical 3 The integrating design of CPU circuit can improve its performance. 4 Light weight and thin design. Technical Specifications: Transmission InterfaceWireless 2.4G RFBattery Capacity600mAWorking PrincipleElectromagnetic inductionVoltage4.8VDate-Signaling Rate19200 Baud rateElectricity50mA-100mAWorking Temperature-20°C 55°CActive Area204mm*154mmPower SupplyUSB/BatteryDimension256mm*250mm*30mmBattery TypeRechargeableWeight500g (including battery)