The new ER•20XS is the highly-awaited next generation of Etymotic’s industry-leading ETY•Plugs® High-Fidelity Earplugs. ER•20XS eartips are interchangeable. ER•20XS earplugs can also be used with foam eartips with essentially no change in response. 20-dB equal sound reduction across the spectrum of hearing. 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.