The Rousseau ER50 Custom Alto Saxophone Mouthpiece provides focus without restriction, allowing players to achieve a flexible sound with great warmth and shimmering tone color. The increased resistance of this mouthpiece allows for great control, especially in the altissimo register. The tonal stability and clarity this mouthpiece provides is unmatched. The ER50 Custom delivers a measured response, feel, and tone, yet still delivers the Rousseau magic tone from the unique designs of Dr. Rousseau's chamber and baffle.