UHF latest wireless technology, stable signal, no delay, no interference from home WIFI signal. Transmission distance up to 160 feet in open area. Use up to 15 sets at the same time Built-in highly sensitive condenser microphone, perfectly capture the soundtrack of the instrument, make the sound more clear and realistic The wireless instrument microphone with LED digital screen that can see the Frequency / Battery Power and Volume easily 360-degree rotatable silicone shock-proof clip and strong steel collar clip make it easy to fix on instruments or collar. It can effectively filter the noise generated by the vibration of the instrument The wirelss mic is compatible with voice amplifier, speaker system, etc. Apply for concerts, band performances, personal exercises, band exercises. Wind music wireless microphone, suitable for all kinds of brass instruments such as trumpet, large, horn, trombone Included a free 3.5mm(1/8") to 6.35mm(1/4”) adapter Built-in 2x 400mAh rechargeable lithium-ion battery, 2 hours charge, 5-6 hours available, red light on when charging, red light off when fully charged Specifications: Frequency range: 550.5MHz 589.5MHz Frequency response: 30Hz-16KHz Transmit power: 16dBmr Microphone sensitivity: ≤-106dBm Distortion: <1% (1KHz) Working frequency: 15 working frequency Built-in battery: 3.7V 400mAh x2 Life time: 5- 6 Hours What to do if there is no sound: Turn on the transmitter, long press and hold the "+" button on the transmitter, when the red light "-" on the display flashes and then releases. Turn on the receiver at the same time and wait for pairing, blue light on receiver will flash. After a few seconds, the transmitter display is normal and the receiver blue light is on(stop flash). That's means paired successfully. Note: Do not support for Macbook/laptop/PC/mobile. Not compatible with the audio equipment without "Mic" jack. Please kindly read the user manual before using it and there will be some suggestions for your reference when you have a problem.