Patented design blocks low and medium frequencies while higher frequencies [voice, signals, alarms] can be heard more naturally, with less distortion. Prevents worker isolation by enhancing communication. Low attenuation ideal for marginal noise environments of 95 dB or lower, preventing overprotection and improving overall worker safety and compliance. Patented quadruple SoftFlange™ design creates comfortable seal in the ear canal for all-day comfort. Two sizes fine-tune fit for personal comfort and safety. Cord Adjuster adapts length to suit personal preference or application. Woven cord reduces sound transmission when earplugs are worn. Reusable case with hook allows wearers to attach to belt loop, apron, bag or other work tools.