Put Howard Leight SmartFit Earplugs into your ear canal, and the temperature of your body heat will soften the material so that it molds perfectly to the shape of your ear. That's the new technology that makes SmartFit reusable ear plugs more comfortable for most users — right out of the box! SmartFit ear plugs also come with a hefty SNR 30dB rating for a high rating for common noise levels, a unique removable cord system, and a handy HearPack™ storage case. These foam plugs are metal detectable and can be used in assembly lines where metal detectable devices are installed.