Tested according to ANSI S3.19-1974, Radians made in the USA disposable foam Ear Plugs feature soft, slow recovery foam for extreme comfort and outstanding noise reduction to protect your hearing. The FP31MD has embedded metal in the Ear Plug 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 available in a corded option and are conveniently packaged in individual polybags to keep each pair clean.