Record voice memos, classes, and lectures easily with this Sony TCM-500DV portable cassette recorder. It uses 2 AA batteries and provides up to 22 hours of operation per set of fresh alkaline batteries. Adjustable playback lets you accelerate or reduce speed slightly during play for custom listening comfort. Listen through built-in binaural speakers or privately with an optional stereo headphone. Built-in flat microphone is highly sensitive for optimal pickup. Overall, a dependable, reasonably rugged recorder that's designed to do a great job - and does it superbly.Voice Operated Recording activates the recorder only when audible sound is present, conserving tape and eliminating soundless passagesExternal Microphone Jack allows connection of an external microphone for special recording applicationsPlayback Speed Control lets you adjust playing speed as much as +30% or -15% for easier review of recorded information.Up to 22 Hour Battery Life using advanced, efficient circuitryClear Voice Recording System sound system enhances voice quality during recording and playback for greater clarityDual Playback SpeakersAutomatic Shut-Off At End of Tape helps reduce mechanical wear, reduces battery consumption, and lets you know when you have reached the end of the tape.Sony-Matic Automatic Recording Level Control uses advanced circuitry to ensure correct recording levelL/R Monaural Earphone JackCue, Review, Pause FunctionsFrequency Response -250-6,300 HzUses 2 AA batteries (not included)Unit Dimensions(WxHxD) -3-1/2 x 4-1/2 x 1-1/2 inches / Weighs 10 ounces with battery and tape installed