Very suitable for teachers, lectures, scholars, etc.Small size for long time wearing.A wide range of frequency bands provides better reception and transmission performance.The system can be powered by batteries and is more convenient.With a valid range of up to 20 meters, you don 39;t have to worry about the signal. Type: Lapel MicrophoneFrequency: 80-12500HzOutput: 600 OhmsEffective Range: 20mTransmitter Battery: 1 x 1.5V AAA Battery (Not Included)Receiver Battery: 6F22 9V Battery (Not Included)Receiver Size: 98mm x 63mm x 28mm/3.86inch; x 2.48inch; x 1.10inch; (Approx.)Transmitter Size: 105mm x 40mm x 14mm/4.13inch; x 1.57inch; x 0.55inch; (Approx.)Length: 95cm/37.40inch; (Approx.) Notes:Due to the light and screen setting difference, the item 39;s color may be slightly different from the pictures.Please allow slight dimension difference due to different manual measurement. Package Includes:1 x Receiver1 x Transmitter1 x Lapel Microphone1 x English User Manual