Califone Sentinal MP3 Player 8104 - Sentinel feature enables teachers to set the maximum audio allowed to 85 decibelsdual headphone jacks, making it ideal for learning centers, language labs and libraries, built-in electret microphone, enabling student-created podcasting, rugged ABS plastic for durability and classroom safety, includes one 1114 AVPS Jack Box & 4 3060AVS headphones.