In principle, the Sennheiser RS4200 is a good device, but interferes with the frequently occurring after approximately 2-3 hours "Beep" as a signal for the end of the battery capacity very. The battery lasts for a few hours with frequently repeated beep-beep, but does not reach the spezifierten 9 hours of operation. Whether the cause is a device failure of the RS 4200 or the new battery, remains unclear.
