Feature 1Manual Knob: FM transmitter pickup module uses manual knob to find the station more accurately, you need to manually input the receiving frequency carefully, such as input 88.1MHZ ,88.2MHZ, 88.3MHZ.... .108.0MHZ. 2Long Range: FM emission mic core board using 9V power supply, 0.7m/2.3ft wire as antenna, open place transmitting distance of 50100m/ 164.0328.1ft, the actual communication distance varies depending on the environment, antenna location, receiver Sensitivity, etc. are different. 3Through the Wall: FM transmitter pickup board can penetrate the wall, depending on the wall reinforced concrete structure, thickness and density, the general wall can wear 23 block, through the wall capacity by the specific antenna placement, battery voltage, radio sensitivity decision. 4Battery Power Supply: FM transmitter pickup module can use common batteries, the higher the working voltage the greater the transmitting distance, the greater the battery capacity the longer the working time, the actual working time to the actual battery capacity shall prevail. 5Parameters, Materials: FM radio transmitter module working voltage is ultra wide 0.7V to 9V; frequency adjustment range is wider than 88108MHZ. premium PCB material, high density, safe and reliable, aging resistance.Item Type: FM Transmitter Pickup ModuleMaterial: PCBOperating Voltage: Ultra Wide 0.7V to 9VFrequency Adjustment Range: Wider Than 88-108MHZTransmitting Distance: 9V Work, Using 70cm/27.6in Wire for Antenna, Open Place Transmitting Distance of 50100m/ 164.0328.1ft, The Actual Depends on the EnvironmentThe Relationship Between Operating Voltage (Volts) and Supply Current (mA) and Transmitting Power (dBm) is as Follows:9V, 24 mA, 10.2 dBm (That is, 11 mW)8V, 21 mA, 9.5 dBm7V, 19 mA, 8.5 dBm6V, 17 mA, 7.1 dBm5V, 14 mA, 6.1 dBm (Approximately 5 mW)4V, 12 mA, 4.5dBm3V, 9 mA, 2.2dBm2V, 6 mA, -1dBm (~1 mW)1.5V, 4.2 mA, -4 dBm (About 0.5 milliwatts, the general home environment is enough to transmit, green radiation is small!)1V, 2.4 mA, -9 dBm0.7V, 0.9 mA, -20 dBm (That is, 0.01 milliwatts) .wang-edit-text{ font-family:'Arial' !important; } .wang-edit-text table { border-top: 1px solid #000; border-left: 1px solid #000; } .wang-edit-text table td, .wang-edit-text table th { border-bottom: 1px solid #000; border-right: 1px solid #000; padding: 3px 5px; } .wang-edit-text table th { text-align: center; }Package List2 x FM Transmitter Pickup ModuleNoteIt is not recommended to use the earphone wire as the receiving antenna for the mobile phone, which has low sensitivity and large interference, and the effect is affected.