From Warburton:
 
The unique combination of internal shapes controls the airflow to achieve balanced resistance
The internal taper through the throat section plus the reverse bell flair expands and focuses the buzz
Promotes the natural position of the embouchure as if playing the instrument
Provides resistance similar to your instrument for a natural, relaxed feel
Portable - take along everywhere you can't bring your horn
Indestructible - made from tough Delrin plastic - great for students!
Lightweight and easily Portable - keep one in your pocket
Convenient for a quick and effective warm-up
Designed and Manufactured in USA at the Warburton Factory
Terry Warburton has successfully developed THE BUZZARD to achieve the maximum buzzing potential at a very affordable price