Each WhisperPhone Duet includes two handsets and an expandable voice tube that can be expanded up to 6 feet. This teaching aid allows for a quiet classroom during paired reading activities, or for teachers to work one-on-one with a learner to identify which areas of their speech need improvement. Designed as a focused auditory input tool, the WhisperPhone allows learners to receive immediate feedback on their speaking volume, pitch, and pronunciation - among other things! This innovative reading phone provides learners with a multisensory experience in both individual and group activities. Experts in the field have researched and proven the effectiveness of this tool as a teaching aid. Speech-language pathologists have shown the benefits of the WhisperPhone for the classroom or at home. Classpak includes 12 WhisperPhone Duet headsets.