The telex model TDR-5 binaural hearing aid and FM receiver combines two complete body type hearing aids and an FM receiver in a single compact instrument. Designed for use as a binaural auditory trainer or as part of a personal FM system in conjunction with the user's audio input or telecoil equipped hearing aid. Standard metal belt clip, body harness with locking snaps. Ink erasable label for student's name. Protected, flush fitting, plug in channel crystal. High fidelity amplifiers. Two acoustically isolated environmental electret microphones. Automatic "no FM" indicator provides for easy systems checks and warns of FM signal loss. Automatic "low battery" indicator. Separately calibrated "low cut" and "SPL" trimmers for the left and right audio channels. An FM level trimmer with a 12 decibel range boosts the fm signal above the gain of the hearing aid section. Auxiliary input jack for use with television, tape recorders, and other audio-visual units. Rechargeable with either a classroom size tc-series charger or a jack type AC-1 charger. Can use AC-1 charger for operating power. Separate fm and hearing aid function switches and left and right volume controls. Specifications as follows. Hi average full on gain 66 decibel normal response, 63 decibel wide response, 70 decibel power response. Maximum gain, 72 decibel, 68 decibel, 78 decibel. Reference test gain, 56 decibel, 51 decibel, 60 decibel. Frequency response normal tone, 50- 5000 hz, 20-6500 hz, 50-3700 hz. Low cut 100-5200 hz, 50-6600 hz, 100- 4700 hz. Equivalent input noise 25, 28, 25 decibels. Battery type, rechargeable NI-CD, 9 volt, 100 MA capacity. Battery operating time FM and hearing aid 10 hours type, 9 hours minimum, hearing aid alone, 16 hours type, 14 hours minimum. Size, 2.3 by 1.13 by 3.7 inches. Weight with battery, 6 ounces.