UHF wireless acoustic transmission receiver. With 6 selectable channels, and effective range is up to 100 meters. Complex interference-free circuit for using more than 4 sets simultaneously without mutual interference. PLL frequency synthesis technique for stable signal transmission. Dynamic expanding circuit for high S ratio. Low power consumption design for long time usage. Receiver use LCD-display to indicate frequency, channel, battery, level status. Suitable for wireless tour guiding, simultaneous translation, audio-visual education, etc. Frequency Control: Phase Locked Loop(PLL) Frequency Range: 780-789MHz Effective Range: 100 Meters Number of Channels:6 Operating Current: 70mA10mA(Receiver) Receiver Frequency Response: 30Hz-15kHz S Ratio: 50dB Receiving Sensitivity:S 12dB 3uV Power Supply: 2x1.5V AA Batteries (not included) Colour:Black Material:Plastic + Metal Package Contents: 1 x WTG-500R receiver 1 x earphone Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.