[. . . ] RI 250-J Infra-red mono stethoset receiver, designed for use as a personal sound amplifier in conjunction with a hearing aid for people with impaired hearing. It can also be used as an additional receiver for the Set 250 infra-red mono transmission system. The RI 250-J has an additional audio output for connecting an induction loop which allows its use with a hearing aid. RI 500 Infra-red stereo stethoset receiver, designed for use as a personal sound amplifier. [. . . ] It can also be used as an additional receiver for the IS 500 infrared stereo transmission system. According to current scientific knowledge, sound transmission by infrared light poses no risk to health whatsoever. Fluorescent tubes and digital controls do not use this frequency range. Lightweight and extremely comfortable to wear - the receiver weighs only 45 g, including the rechargeable accupack!When the accupack becomes weak (noise interference and sound distortion are sure signs of a weak accupack), switch off the receiver and recharge the accupack. (If necessary, use a second accupack to listen while the first accupack is being recharged. If the accupack is flat but is left in the switched on receiver, this reduces the service life of the accupack ("total discharge"). As far as possible, use the full capacity of an accupack before you recharge it. Frequent short discharge and recharge cycles prematurely reduce its charging capacity. CHaRGInG tHe accupackS the stethoset receivers are powered by ba 151 accupacks which can be recharged either separately or in the receivers. Alternatively, the ezI 120 induction coupler can be connected by means of the ka-1k connection cable. Your Sennheiser dealer will be happy to provide you with information on binaural solutions. CHannel SelectoR SwItcH on tHe HDI 1029-PLL8 the HDI 1029-PLL8 stethoset receiver features a channel selector switch which lets you choose between the following options: With the switch set to position "", a stereo signal is received (channel 1 right, channel 2 left). With the switch set to position "I", only the signal from channel 1 is received (carrier frequency 2. With the switch set to position "II", only the signal from channel 2 is received (carrier frequency 2. CleanInG / ReplacInG tHe eaR-cuSHIonS use a damp cloth for cleaning your stethoset receiver. The ear-cushions can easily be removed from the headphones and cleaned with warm soapy water. From time to time, however, the ear-cushions should be replaced for reasons of hygiene. Replacement ear-cushions are available with different degrees of softness: Please order your ear-cushions from your Sennheiser dealer. enVIRonment anD HealtH Devices powered by rechargeable accupacks are kind to the environment. [. . . ] Replacement ear-cushions are available with different degrees of softness: Please order your ear-cushions from your Sennheiser dealer. enVIRonment anD HealtH Devices powered by rechargeable accupacks are kind to the environment. Conventional batteries, on the other hand, must be disposed of as special waste after they have been used just once. If an accupack should be defective, it is then recycled - the dealer who sold it to you will take it back and will also supply you with a new, original Sennheiser accupack. [. . . ]