Features: UHF technology with low power consumption, high anti-interference capability, and use distance up to 40m(without obstacle). Frequency modulation; Up to 40 units can be used simultaneously without crosstalk or interference. Condenser microphone, high sensitivity, clear vocal. Built-in 400mAh Li-ion battery lasts for 6h operation. Suitable for use with amplifiers or speakers in speech, teaching, tour guide, promotional activities, etc. Specifications: Material: ABS Frequency Response: 60Hz-16KHz Frequency Range: 630MHz-890MHz Operation Voltage: DC2.5-5.5V Battery: Li-ion battery 400mAh Charging Voltage: DC 5V-200mA Charging Time: approximate 2.5h Operation Time: 6h Sensitivity: -51- 54dB Operation Range: about 40m in open area Net Weight: Receiver: 23g, Headworn microphone: 38g Item Size: 80 x 28 x 15mm / 3.15 x 1.10 x 0.59in Package Weight: 142g / 5.02oz Package Size: 18.5 x 14.5 x 4cm / 7.28 x 5.71 x 1.57in Package List: 1 x Headworn Microphone 1 x Receiver 1 x Charging Cable 1 x Manual (English) Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.