... adverse effects on physiological. You need earplugs to against noise. Function: To improve sleep, focus, such as the protection of ... hearing. Noise value (NRR) 25 dB, the smooth surface, with treatment, wearing health, safety, soft, comfortable, good sound effects. ... respirator, gas masks , safety goggles, earplugs and safety helmet with our own brand polyGard and other OEM. These products meet ...