Main Features:�� Compact and beautiful: Mini transmitter and receiver， easy to carry. Can be put in bag�� Excellent sound effect: You will receive good teaching effect when used in class�� Simple operation: The receiver can be plugged in any amplification device which microphone can be used�� Widely used: Suitable for teaching， lectures， guide， driver training， dance training， meeting， performances and home entertainment and other occasions， especially perfect for those who needs often go out to give lectures or the scene where there are amplifier and speaker�� Output impedance: 600 ohm�� Power supply: Powered by 1 x 9V battery ( for transmitter ) ( included��Power by 2 x 1.5V AAA battery ( for receiver ) ( included���� Effective distance: About 50mType: WirelessConnection: 3.5mmFrequency Range : 165 - 270MHzPackage weight: 0.44 kgPackage size (L x W x H): 26.500 x 14.500 x 7.000 cm / 10.433 x 5.709 x 2.756 inchesPackage Contents: 1 x Headset Microphone， 1 x Clip-on Microphone， 1 x Receiver， 1 x Transmitter， 1 x 3.5mm to 1/4 inch Adapter Cable， 1 x 9V Battery， 2 x 1.5V AAA battery