Custom-made silicone earplugs can have a maximum noise reduction (NR) rating of 24 to 28 decibels, which meets standards for CSA Classes A and AL. Their effectiveness depends on how well they fit your ear canal, sowork with your audiologist to get the best fit. Soundwave Hearing Care also provides filtered custom earplugs that can provide a range of noise reduction, depending on your listening and protection needs.