Micro EarPiece Secret-Ear technical data Micro Ear Piece Secret Ear receives signal, by inductive coil, across electromagnetic fields Receiving distance: 50 70 cm (not for Bluetooth solution) Standard Zinc-air battery: type 5 1,4 volt; type 10 - 1,4 volt or type 312 - 1,4 volt Battery life: from 50 to 100 hours Audio bandwidth: from 200 Hz to 4 KHz Size: 12 X 6 X 5 mm. Working frequency : ALL ...