In my early bass years, this mute helped my sound tremendously! The resistance really forces you to open up your throat and play with lots of air - especially in the lower register. I still use it as a warm-up tool (just blowing through the horn without worrying about what's coming out of the bell). For me, though, constant use caused some bad articulation habits. It's a pretty heavy metal mute that likes to work loose and fall out of the bell. It IS really quiet, but because of its stuffiness, I would NOT recommend it as a practice aid.