First portable language learning equipment in the world. The sound of cassette tape and user's own voice can be heard at the same time. Listening one's own voice helps memory works to be effective in learning a foreign language. Can help vocabulary an sentence studies as well as pronunciation practice. Equally effective in memory works in other subjects than languages. High quality sound renders to sing more emotionally. Using as an earphone with switched off consumes no battery. Can also be used as internet-phone. * A user's voice as well as the sound from the cassette could be heard through the earphone. * A user's voice could be compared with the sound from the cassette which is simultaneously recorded. * Infinite Repetition Function * A user's voice could be heard along with "Infinite Repetition Function" (which functions as a "Voice Pen") * Could be used independently of an external sound device which has been removed * Memory Time: 20 seconds * Battery Life Time: 12hrs when the memory is continuously used Packing unit : 30EA/BOX Quntity : 500BOX/20FT ,1000BOX/40FT