Monitor System 518& 8209;554MHz Professional IEM System Receiver for Studio Band Rehearsal Live Performance Feature: 1. UNLIMITED: There is no limit to the number of S3 receivers that can be used at the same frequency. 2. LIGHTWEIGHT AND PORTABLE: The compact bodypack receiver is easy to be tied to a belt or guitar strap. 3. DURABLE: The shell is made of tough ABS material, which is the best choice for display products. 4. APPLICABLE EQUIPMENT: 8 hours battery life (normal), suitable for S3 wireless earphone monitor ear return system. 5. FINE WORKMAN: Adopt advanced circuit design and excellent chip to eliminate the dead angle of receiving and the signal is stable. Specification: Item Type: Wireless Monitor System Material: ABS Frequency Band: 518-554MHz Frequency 518-554 MHz Adjacent Channel Rejection ≥ 70 dB Intermodulation Attenuation ≥ 70 dB Receiving Sensitivity 20 dBuV Antenna 1/4 Wavelength for Braid Antenna Headphone Output Interface Approx. 3.5mm/0.13in Interface Stereo Jack Headphone Output Power 100mW (32 Ohm) Maximum Current About 190ma Battery Life 8 Hours Receiver Battery: 2xAA Batteries (Not Included) Headphone Output Interface: Approx. 3.5mm/0.13in Stereo Jack Package List: 1 x Receiver 1 x Headphone 2 x Pair of Ear Caps Note: Battery is not included. How to use: 1. Install the battery 2. Connect the transmitter to use