Features: 1) Phase Lock Loop Technology (PLL) 2) 900MHz RF technology 3) RF technology lets you roam freely throughout your house 4) Built-in auto pin charger in the transmitter 5) Virtually interference free stereo quality 6) Automatic Level Control and auto ON/OFF control 7) Auto-Tuning Function 8) 6dB Sinad Specification 1) Transmission Model: UHF Stereo 2) Operation Voltage: A. Transmitter- 12.5V 150mA, B. Headphone-2.4V (2*"AAA" Rechargeable Batteries) 3) Frequency Response: 30Hz ~ 12KHz 4) Distortion: 1.5% 5) S/N Ratio: 50dB 6) Separation: 30dB 7) Operation Distance: 50M