The Radio Shack CTR-111 Portable Cassette Tape Recorder & analog phone Call Recording Device Its features include: Automatic Stop - protects the tape and tape handling parts by automatically stopping the tape when it reaches the end. Automatic Level Control - ensures quality recording by automatically (ALC) Circuit setting the proper recording level. Record/Battery Indicator - lets you know when the CTR-111 is recording or when the batteries need replacing. Built-In Condenser Microphone - lets you create quality recordings in situations that require a microphone with high-sensitivity, such as conferences or lectures. MIC Jack - lets you connect an optional external microphone for unidirectional recording, reducing background noise. Remote Control Jack - lets you connect an external microphone that has an on/off switch, so you can control the CTR-111 from your microphone. Supplied Earphone - so you can listen in private. Auxiliary Input Jack - lets you connect a radio, tape deck, or CD player so you can record from these external audio sources. Three Power Options - lets you power the CTR-111 from four C batteries (not supplied), standard AC power (with an optional AC adapter), or your vehicles battery (with and optional DC adapter). Supplied Erasing Plug - plugs into the external microphone jack so you can erase a cassette tape by recording silence. Retractable Handle - lets you easily carry the CTR-111.