Long Transmission Distance. 9V work when using the 70 cm antenna conductors, open firing range 50-100 meters, the actual situation depends on the environment. for electronics enthusiasts upgrade or replace the chip. Feature - - Material: Plastic+Electronic Component. - Size: 3.5 x 1.5 x 1cm. - Operating voltage: 0.7V - 9V. - Frequency adjustment range: 88-108MHZ. - Relations Working voltage ( ) and supply current (mA) and transmit power ( ) is as follows: 9V, 24mA, 10.2 (that is, 11 mW) 8V, 21 mA, 9.5 7V, 19mA, 8.5 6V, 17mA, 7.1 5V, 14mA, 6.1 (about 5 mW) 4V, 12mA, 4.5 3V, 9mA, 2.2 2V, 6mA, -1 (about 1 ) 1.5V, 4.2mA, -4 (about 0.5 mW, the average family environment launch sufficient, small green radiation!) 1V, 2.4mA, -9 0.7V, 0.9mA, -20 (that is 0.01 mW). - Listen with any or . - Many uses, baby monitor, nature monitoring, home security, use to add sound to home recording system or listen to sound from a parked car. - Transmitting very clear sound to distance about 10-30 meters. Package list: 1 x Micro