Professional Universal UHF Wireless Conference WM3000U With Rechargeable Battery. PERFORMANCE AND SPECIAL with automatic mute and shock elimination circuit,to avoid the stroke and noise of the switch. Thenconference microphone has an LED digital tube display, can directly the current display frequency. wireless transmission effective distance 30-50meter conference microphone adopts lithium battery circuit design, with overcharge and over discharge protection. simple operation interface,very small adjustable components,can completely avoid malfunction caused by malfunction. Launch conference microphone has a low voltage detection and the battery character flashes when the battery voltage drops to 2.2V. Extremely high sensitivity and excellent sound quality make your talking or singing easy. Multiple devices can be used at the same time,without interference and frequency. with power and wireless indicator lights Support single frequency Support to the unit in the preparation of the main technical. PERFORMANCE AND SPECIAL 2.1 TRANSMITER TECHNICAL SPECIFICATION Frequency:667.50-696.00MHz the channel number of 48(conservative). Oscillation mode DSP chip frequency lock Frequency stable ±10ppm RF efficiency 10dBm FG40-18000Hz Distortion ≤0.5% Battery specification 1.5V/AA Size Alkaline battery Renewal time 4-8hours (depending on battery typr and capacity. 2.2 RECEIVER SPECIFICATIONS Frequency:667.50-696.00MHz the channel number of 48(conservative). Oscillation mode DSP chip frequency lock Frequency stable ±10ppm Bonding instruction -95~-71dBm FG40-18000Hz Distortion ≤0.5% Signal ratio ≥90dB Audio output 300mv (maximum)