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 WORKMANSHIP: Adopt advanced circuit design and excellent chip to eliminate the dead angle of receiving and the signal is stable.Specification:Item Type: Wireless Monitor SystemMaterial: ABSFrequency Band: 518-554MHzFrequency 518-554 MHzAdjacent Channel Rejection 70 dBIntermodulation Attenuation 70 dBReceiving Sensitivity 20 dBuVAntenna 1/4 Wavelength for Braid AntennaHeadphone Output Interface Approx. 3.5mm/0.13in InterfaceStereo Jack Headphone Output Power 100mW (32 Ohm)Maximum Current About 190maBattery Life 8 HoursReceiver Battery: 2xAA Batteries (Not Included)Headphone Output Interface: Approx. 3.5mm/0.13in Stereo Jack.Package List:1 x Receiver1 x Headphone2 x Pair of Ear CapsNote:Battery is not included.