... or usb headset 3,page turner:page up/down 4,laser pointer,MP3 play 5,LCD diplay mic teaching aids & teaching microphone ... battery,signal link,volume and so on.6. Remote electronic laser pointer,page turner, USB upgrading.7. Pen designed,instead of any ... .7V Alkaline battery Working Distance: ≤80 meters Working Temperature: -30-50°C Weight: 45G Dimension: 95.5*33.5*18(mm ...