Features: It makes the sound around the microphone into the FM radio and transmits out to achieve pickup and wireless radio FM transmitter. Wide voltage range: 0.7-9V. Under the condition of 9V and use of 70cm antenna, the launch distance is 50-100 meters in open space (depends on the actual environment). 88-108MHz adjustable launch frequency, more flexible to use in different situations. Widely used in voice pickup transmission, audio MIC, the elderly and children sleep monitoring, etc. Brand new material and high quality. Compact and lightweight. Note: 1. Please allow 1-3mm error due to manual measurement, thanks for understanding. 2. Color may be slightly different due to different lighting conditions and monitor settings, please in kind prevail. Specifications: Color: Green Operating Voltage: 0.7V-9V Frequency Adjustment Range: 88-108MHz Transmission Distance: Under the condition of 9V and use of 70cm antenna, the launch distance is 50-100 meters in open space (depends on the actual environment) Relationship between Working Voltage (volts), Supply Current (mA) and Transmit Power (dBm): 9V, 24mA, 10.2dBm (that is, 11mW) 8V, 21 mA, 9.5dBm 7V, 19mA, 8.5dBm 6V, 17mA, 7.1dBm 5V, 14mA, 6.1dBm (about 5 mW) 4V, 12mA, 4.5dBm 3V, 9mA, 2.2dBm 2V, 6mA, -1dBm (about 1mW) 1.5V, 4.2mA, -4dBm (about 0.5mW, the general family environment launch is sufficient, small green radiation!) 1V, 2.4mA, -9dBm 0.7V, 0.9mA, -20dBm (that is 0.01mW) Item Size: Approx. 5 * 3 * 1cm / 1.97 * 1.18 * 0.39in Package Size: Approx. 5 * 3 * 1cm / 1.97 * 1.18 * 0.39in Package Weight: Approx. 3g / 0.11oz Package List: 1 * FM Transmitter Module Board