Peavey ALSR 75.9 Mhz Assisted Listening Receiver Body Pack ALSR75.9 + Earbuds Peavey ALSR 75.9 Mhz Assisted Listening Receiver Body Pack for ALS 75.9 System. Frequency Response 100Hz  15 KHz, +/- 3dB. Signal-to- Noise Ratio 60dB. Total Harmonic Distortion &lt;0.5%. RF Carrier Frequency between 72-76 MHz. Frequency Stability +/- 0.005%. Modulation FM +/- 75KHz max. Operating Range Up to 300 ft. line of sight. Controls  Combination VOLUME/ON-OFF wheel. Audio Output  250 mW max into 16 ohms. Connectors  3.5mm mini jack for earphone output. Earphones  Mini binaural ear buds. Antenna  Integral with earphone cord. Indicators  LED power on indicator. Sensitivity  2 uV for 12 dB Sinad with squelch defeated, Squelches at 10 uV for min. 50 dB S-N ratio. Mute Threshold  8-10 uV. Power Requirement  (2) AA Batteries. Battery Life  17-20 hours with alkaline battery. Dimensions  110 x 60 x 20 mm. Weight 2.75 oz without batteries (80g). Peavey ALS Ear Buds for Assisted Listing System Replacement Standard Ear Buds. Not a complete system. You will need to add a transmitter and receiver.