The 3M E-A-Rsoft ear plug is made of polyurethane foam, is packaged 2000 pair per case, comes in yellow and meets CSA Class AL standards. Proper sizing is important when buying this SKU. The size for this product is Medium. Some products are single use while others are reusable. This particular ear plugs is disposable. Ear plugs can come in many different shapes and colors. This ear plus is cone shaped.