This system is designed to help someone better hear what is being sent over in-room audio system. These systems are usually stored in a closet near the classroom so they can be recharged. Check with the facilities person for your building to get the system.
The hearing system works similarly to ones you may have seen in a movie theater. Audience members will use the pack with headphone which will amplify the lapel-style microphone when worn by the instructor. If the instructor needs it, then the instructor can wear the pack and audience members will need to share microphones when speaking.