?Features: It consists of a transmitter， receiver， two piece of earphone( one is with speaker)， an audio signal cable， a lavalier/lapel microphone. Experience more freedom of movement while recording . Excellent sound quality， great portability， easy setup . Two way communication system. Approximate 50m(164ft.) operation range. Compact， high performance， lightweight. The receiver with standard hotshoe， compatible with DSLR cameras， camcorders， audio recorder etc.. Specification: RF Modulation: GFSK (Gauss Frequency Shift Keying) Frequency band: 2.4GHz (2405-2478MHz) Frequency response: 35Hz-14KHz±3dB Signal/Noise: 76dB or more Distortion: 0.1% or less (32ω， 1 KHz， 65 mW output) FR output level: 5 mW Earphone output level: 32ω， 65mW Reception sensitivity: -85dB+/- 3dB / 0dB=1V/Pa， 1KHz Audio input connector: 3.5mm mini jack Operation range: 50m (164 ft) Power requirement: 2 * AAA batteries(not included) Consumption power: Transmitter: 3.3V/110 mA? ? ? ? ? ? ? ? ? ? ?Receiver: 3.3V/100 mA Package size: 15.2 * 10.8 * 6.3cm / 6.1 * 4.3 * 2.5in Package weight: 250g / 8.8oz Package List: 1 * Transmitter? 1 * Receiver 2 * Earphone( one for speaker) 1 * Audio Signal Cable 1 * Lavalier Microphone 1 * Manual (English & Chinese)