Uniquely designed for smaller frames with a open bell on one side coupled with a traditional diaphragm on the other side. A 7 rating on a scale of 1-10 for performance represents its acoustic quality. Comfortable fit and excellent acoustic seal with patented 3M Littmann Snap-Tight Soft Sealing Eartips. You will get high quality sound transmission with its anatomically designed headset which strategically and comfortably fits in your ear. Durability is demonstrated by the fact that the headset can be reliably flexed one million times. Patient comfort is assured when using the nonchill rim and diaphragm.