Moldex SparkPlugs Earplugs are made of extra-soft, extra-light foam. Their tapered shape fits easily in the ear canal, and seals gently and snugly without pressure. Theyâ€-re so comfortable youâ€-ll forget youâ€-re wearing earplugs. The noise reduction is rated at 33 dB. SparkPlugs also come in a metal detectable version which has a new metal detectable cord. The bright blue color is perfect for food processing applications. The enclosed metal ball bearing eliminates any exposed metal. The ball bearing and cord are in separate holes so that the earplugs remain detectable even if the cord is removed. The earplugs are corded to prevent earplug loss.