SONY TCM210DV STANDARD CASSETTE VOICE RECORDER WITH AC ADAPTER & CASSETTE Includes AC adaptor and cassette to conserve batteries and provide virtually unlimited recording and playback time when an AC power source is available External microphone jack allows connection of an external microphone for special recording applications Built-in microphone for extra convenience eliminates the need for an external microphone in many situations Large playback speaker for Improved Sound Sony-Matic automatic recording level control