The artino Heavy Metal covered with rubber practical mute for cello is a traditional dumb heavy metal with a durable rubber coating. This rubber coating is designed to protect your deck and instrument. Like other muted heavy metals, it allows you to practice without disturbing others and with the rubber coating reduces the noise level to a minimum while maintaining a quality sound. It takes a few seconds for it to fit on the deck and is one of the muted best practices we have found. This model is designed for a student.