... surface by anti-pollution treatment 3,wearing health,safety,rebound Ear plug with metal case Hot sale gift 2012 - Fluorescent yellow Unfading ... , noise effective,SNR:33DB, This earplug can be washed with water, reuse. Name Material Model standard earplugs slowPU HY- ... small to close contact with the externalear canal, noise effect will be reduced. So we must observe ear plug and play back ...