3m™ e-a-r soft metal detectable earplugs, corded, poly bag, 311-4106, 200 pairs 3m™ e-a-rsoft™ metal detectable earplugs were specially developed for food processing and other industries where it is critical to keep earplugs from contaminating products and processes. Recognized by most metal-sensing systems, these earplugs feature an implanted stainless steel ball bearing in the plug and metal particles in the cord. Benefits: implanted stainless steel ball bearing in the earplug and metal particles in the cord poly bag keeps each pair of earplugs clean before use regular size fits most earcanals noise reduction rating (nrr)*: 32 db.