The Deluxe Series of stereo and monaural headphones are longstanding teacher favorites (and student-tested) for literacy and language learning activities, computer-related classes classrooms and libraries.Califone understands equipment that's used repeatedly in classroom learning needs to be made to a higher standard. Safety features begin with slotted earcup baffles on all 2924 headphones protect the internal speakers against accidental perforation by sharp objects such as an unfolded paper clip or scissors. Noise-reducing earcups help hearing safety by resting around students' ears (not in them) to provide maximum protection against external noise, minimizing distractions so students won't increase the volume to hear the content. The rugged ABS plastic construction won't shatter (unlike materials used in consumer electronics items) into potentially dangerous shards and withstand the rigors of daily use.The entry point of the 6' straight cord into the earcup is reinforced against accidental pull-out and is permanently attached on the stereo model. For the monaural version, choose between coiled and straight cords.The 3.5mm stereo plug on the stereo models enable students to listen to smartphones, tablets, computers and other audio sources and comes with a ¼" screw-on adapter. The 1/4" plug on the monaural models connects the headphones with cassette player/recorders. Both the 3.5mm and ¼" plugs can be used with jackboxes for group listening center activities.The stereo models offer volume control on the earcup while most monaural versions do not (the mono 2924AVPV does).Choose between beige or blueberry colors and gray is also available for monaural.The headphones are available as a classroom pack of twelve units with storage case (mono 2924AVP-12 or stereo 2924AVPS-12), a classroom pack ten monaural headphones without a storage case (2924AVP-10L).Optional disposable hypoallergenic cloth earpad covers (2924EC) are available for headphones in high use settings. Students and teachers tell us the covers help make the headphones feel even cooler, are comfortable to wear and help keep the earpads clean. For heavy-use situations in libraries, language labs and speech pathology applications ABS plastic earcups and adjustable headband for durability Replaceable foam-filled ear cushions Replaceable clip-in 6' straight cord with 1/4" plug Around-ear ambient noise-reducing earcups deliver maximum protection against exterior sounds (without added electronic circuitry and expense). This reduces the need to increase the volume (protecting the ears) and helps keep students on task.