What is the difference between the Interacoustics AS608B and AS608E audiometers?

AS608B - Robust construction, Customize frequency test selections, Output levels from -10dB to 100dBHL, Pure tone, warble tone and pulsed tone , Silent stimulus switch , Battery status indicator , Carrying bag, External power supply (optional), Noise reducing headset (optional).

AS608E- Robust construction, Customize frequency test selections, Output levels from -10dB to 100dBHL, Pure tone, warble tone and pulsed tone , Silent stimulus switch , Battery status indicator , Carrying bag, External power supply (optional), Noise reducing headset (optional).

Plus - Talk Forward, Full PC-integration through USB, Hughson Westlake auto pure tone test, Patient response switch.