[. . . ] RS 4200/RS 4200-2 The RS 4200 is an ultra-lightweight RF wireless stereo stethoset headphone system for enjoying TV sound without disturbing others. [. . . ] The transmitter features a compression button for further enhancing speech intelligibility. The RS 4200-2 has the same features as the RS 4200 but includes two stethoset headphones and two Sennheiser accupacks. Reception everywhere Specifications Modulation Carrier frequencies Range Frequency response THD at 1 kHz Max. SPL Audio connection Operating time Charging time Weight (headphones) Weight (transmitter) Dimensions (transmitter) Dimensions (headphones) FM, stereo 863. 3/864. 0/864. 7 MHz up to 100 m 50 Hz ­ 16, 000 Hz <1% 125 dB 3. 5 mm stereo jack socket approx. 150 g 115 x 145 x 95 mm 200 x 135 x 20 mm Ideal for TV sound transmission Freedom of movement within a range of up to 100 metres Sound transmission through walls and ceilings, even in the garden Intelligent auto-tuning ­ headphones with automatic search tuning and memory function Balance control on the headphones for separately setting the volume level for the left and right ear Compression function ensures superior speech intelligibility and very good reproduction of music Three selectable frequencies for optimum reception Lithium-Ion rechargeable battery pack ("accupack") for more than 9 hrs. [. . . ] of audio enjoyment Transmitter recharges the headphones plus an additional accupack Headphones automatically switch on and off when they are put on/removed Includes short instructions and colour-coded sockets and plugs for quick set-up and connection Very lightweight stethoset headphones, extremely comfortable to wear even for extended listening Ideal for wearers of glasses Suitable for plasma TVs [. . . ]