The LR-42 stethoscope receiver is a very easy to use, comfortable and user friendly. This all-in-one receiver can receive up to four (4) channels in mono or stereo. It uses standard AAA alkaline batteries for more than 30 hours of use, or a NiMH rechargeable battery pack that delivers 15 hours of use per charge. The unit features auto shut-off after 30 minutes of no audio carrier, further extending battery life. The LR-42 boasts high performance audio specs in a small package and is compatible with other manufacturers' products. The LR-42 is used for government compliance (such as ADA), assistive listening, language interpretation, live theatre, houses of worship, courtrooms, secure rooms and auditory description.