True two channels - for presentation of 2 different frequencies Air-, bone, speech and freefield (optional) with built-in power amplifier Tone, pulse, warble, masking and CD/tape/microphone input Clinical features such as SISI, DLI, ABLB and Carhart decay testing Complex mixing for presentation of test and masking signal to one ear Optional high tone audiometry for AC up to 16 kHz Optional insert phone capabilities AC with Sennheiser HDA 200