Durable PLASTIC 
Sturdy and long lasting 
Provides necessary protection against bumping or denting 
 
This little end plug fits snugly into the neck receiver of your saxophone, keeping it safe and sound from shifting around while you're on the move. Its most important function is to prevent the delicate octave mechanism from getting bent or damaged since it is a very exposed part of the sax.
 
The end plug helps ensure that the octave mechanism rod and adjustments don't get damaged so you can be ready to rock Careless Whisper at any moment.