The EP4 Sonic Defender Earpieces protect your hearing without interfering with your ability to hear routine sounds or conversations. Their triple-flange stem design fits larger ear canals and provides a Noise Reduction Rating (NRR) of 24dB. Sounds, at safe levels, are allowed to pass through into the ear canal, while potentially harmful noises (above 85dB) are reduced to safe levels via a proprietary design that incorporates the patented Hocks Noise Braker filter. EP4s include attached stopper plugs, which can be inserted for further protection and blocking out lower-level noise, like that heard on a plane, where hearing ambient sounds or conversations isn't critical. The right/left color-coded Sonic Defenders Plus are made from a soft but durable, hypoallergenic polymer and are ergonomically shaped, with an adjustable-stem design, providing a secure fit, all-day comfort, and extended product life (3 to 6+ months, depending on usage and care). And their low-profile design means they can be worn while wearing a helmet or mask, or while using a phone or headset.