... uniform structure, smooth surface withoutadhesive, noise effective,SNR:33DB, This earplug can be washed with water, reuse. Name Material Model standard ... customized according to customer requirements Direction of UseTake out the earplug, with the index finger and thumb to rub fine ... .Low rebound effectIf it is too flexible, anti-noise earplug swelling suppression the canal skin, can cause ear swelling, ...