Wireless In Ear Monitor System 2.4GHz Professional Digital In Ear Monitor On Stage Audio System Features: Universally fit - Support 2.4GHz ISM band with long and stable transmission distance, up to 30 meters wireless transmission. Professional for wireless stage monitoring, studio monitoring, stage sound system, with in-ear headphones to make your performance more smooth. Supports 2.4 GHz digital transmission - Unlike UHF devices' analog signal, 2.4Ghz can realize digital transmission. HD audio - Support 64K@16bit*2 sampling rate, HDCD audio. Almost no delay, stable signal with delay time: 1.1 - 2 ms. This is the shortest delay time in this band. The actual test signal-to-noise ratio is 89dB, and the actual test signal-to-noise ratio is 1.5%. Support up to 6 units to be used at the same time without mutual interference. 1 to many -1 single transmitter can be bound to multiple receivers. The receiver has been adopted by APEC2014 for simultaneous interpretation and deploying staff. Specification: Receiver: Model: WTG02 Material: ABS Weight: Approx. 96g Size: Approx. 10 * 6.5 * 2.5cm Frequency range: 2400MHz - 2483MHz Power: DC 3V (2pcs AA battery, which is NOT included) Frequency response: 20Hz - 20KHz Signal to noise ratio: 89dB TED: 1.5% @1khz Earphone: Frequency response: 20Hz - 22000Hz Impedance: 16Ω Sensitvity: 110 (dB) Transmitter: Material: Aluminum alloy Weight: Approx. 143g Size: Approx. 7.9 * 7 * 2.5cm Frequency range: 2400MHz - 2483MHz Power supply: DC 5V/500mA The power of communication: ≤ 20dB Working range: Approx. 30 meters   Package list: 1 * Receiver 1 * Transmitter 1 * In-ear Monitor 1 * Spare Antenna 4 * Earphone Covers 1 * Instruction Manual 1 * DC Power Cable 1 * 3.5MM Male to Male Audio Cable 1 * 3.5mm to RCA Stereo Cable Note: 1. Please note that there is NO battery in the package. 2. Please allow slight error due to manual measurement. Thanks for your kind understanding.3. Please note that the new type and old type of this product will be sent randomly, and make sure you will not mind before ordering.