1. Higher sound quality and clear duo cone2. Hand-tune design3. The newest structure design concept4. Effective distance for 30 metersTransmitter * Working frequency: 84~87MHz stereo * Power supply: DC 12V * Input impedance: 10kΩ* Transmit distance: max. 500mV Headphone * Working frequency: 85~86MHz * Power supply: 3V (AAA) * Load: 32Ω* Signal/noise ratio: ≤82dB * Frequency response: 50Hz-18kHz * Receiver distance: ≥40 meters (none impediment)