SparkPlugs earplugs are made of extra-soft, extra light foam. Their tapered shape fits easily in the ear canal, and seals gently and snugly. They’re so comfortable you’ll forget you’re wearing earplugs. SparkPlugs earplugs offer the highest independently tested NRR 33, making them suitable for most noisy environments. So, while they look like fun, they provide serious protection. All Moldex hearing protection is independently tested to ANSI S3.19-1974 by Michael & Associates, Inc., State College, PA