The ER·20XS is the next generation of Etymotic's industry-leading ETY·Plugs High-Fidelity Earplugs. ER·20XS earplugs are discreet and have the identical response of ETY·Plugs through 4 kHz. Above 4 kHz they have improved high-frequency clarity without compromising protection. ER·20XS earplugs feature a low-profile, stem-less design that sits snugly in the outer ear without protruding. This makes it especially comfortable to wear under hats, helmets and other headgear. ER·20XS earplugs come with a small, flexible pull tab that allows for easy removal, an easy-to-install neck cord and a carrying case.