Decibullz Custom Molded Earplugs are easily and quickly fitted to the exact shape of your ear for an NRR of 31. Decibullz Custom Molded Earplugs are easily and quickly fitted to the exact shape of your ear. Reusable and extremely comfortable, this creates a perfect fitting, low-profile earplug that will never hurt, never fall out and provide superior noise isolation.Simply heat the Decibullz thermoplastic molds in boiling water, let them cool and shape them to your ears. It's that easy. If you don't get a perfect fit the first time, don't worry. Decibullz are the only custom earplugs that are re-moldable.