The Hamilton Electronics ALS600 delivers superior sound quality in Assistive Listening Systems. Experience a high quality listening experience and ensure ADA compliance at any large venue with our system. One transmitter can serve an unlimited number of receivers within a 300 foot radius. SystemFrequency Response 100Hz-8kHz, +- 3dB. Signal to Noise Ratio 41 dB. Total Harmonic Distortion 0.5%.RF Frequency 75.5 MHz. Frequency Stability better than .005%.Operating Rangeup to 300 feet line-of-sight. Audio Sound Mono. TransmitterMic Input 1/4" Phone jack, unbalanced with 12V DC at 1 mA for condenser mic. Line Input 1/4" Phone jack, impedance: 100K unbalanced. Power Input 15dBm. Controls power on/off, audio input gain adjustment. Indicators power On LED, Audio modulation LED. Antennapermanently mounted telescoping whip antenna. Power Requirement 12V DC regulated at 300 mA. Dimensions 1.25" x 8.25" x4.25".Weight 2.6 lbs. ReceiverControls Separate volume & power controls. Audio Output 109 mW max into 16 ohms. Connectors 3.5mm mono mini jack for earphone output. Earphones Mini binaural earbuds. Antenna Integral with earphone cord. Indicators LED power on indicator. Sensitivity 3 uV for 12dB Sinad with squelch defeated. Mute Threshold 5-8 uV. Power Requirements 9V Alkaline. Battery Life 17-20 hours w/alkaline battery. Dimensions 3.35" x 2.75" x .75".Weight 2.65 oz. without battery.