Etymotic Research ER20XS Motorsport High-Definition Earplugs About this item New, low-profile, stem-less design that sits snugly in the outer ear without protruding. Especially comfortable to wear under hats, motorcycle helmets and other headgear. Reduces sound levels evenly so that speech and environmental sounds are clear and natural. Reduces the potential for hearing damage from loud machinery, vehicles, power tools, sporting events, concerts and recreational activities. Not recommended for use with impulse noise, e.g., shooting sports. Not recommended for sleeping