Listening Centers are great for schools or training programs. They allow for multiple people to listen to the same recording or lesson, while the monitor controls the master volume and content.
Over the ear headphones are larger-sized headphones that completely surround the ear, rather than resting on the ears. They are designed to block out almost all external noise. They tend to be heavier than normal headphones. The two major categories are sealed (made to not only isolate outside noise from coming in, but also to keep headphone noise from leaking so others can’t hear what you are listening to) and open (made to allow some outside noise to come in by using a vented earcup- good for quiet environments and has a more spacious sound).