Tested according to ANSI specs S3.19-1974, Radians Made in the USA disposable foam earplugs feature soft, slow-recovery foam for extreme comfort and outstanding noise reduction to protect your hearing. The FP31MD has embedded metal in the earplug for easy metallic detection. They are easy to roll down and insert, and they expand slowly for a low-pressure fit in virtually any size ear canal. They are packaged in individual polybags to keep each pair clean.