When a sound transmission needs to be recorded use our convenient plug and play wireless microphone set with recording device. Specifications: ¥ Transmitter: ¥ Frequency: F1 171.105MHz-F2 171.905Mhz ¥ FM band ¥ +/-2KHz maximum deviation ¥ DC 3V power ¥ Uses 2 AA batteries (not included) ¥ Power switch ¥ Channel selector switch ¥ LED power indicator ¥ Transmitts up to 100 to 125 feet inside ¥ ¥ Receiver: ¥ Frequency: F1 171.105MHz-F2 171.905Mhz ¥ Sensitivity of 10dB uV for 20dB S/N ¥ DC 3V power ¥ Uses 3 AA (not included) ¥ Power switch ¥ Channel selector switch ¥ LED power on SIZE: 31/4" x 2 1/2" x 1"