Are you trying to sleep in a noisy place or with a loud snoring partner?
Are you a hotelier trying to help your guests sleep more comfortably in spite of noise they can hear from adjacent rooms (or from their snoring bed partner)?
Are you trying to find a hearing protector you can wear to your church where the music and/or the public address system are too loud for your comfort?
Are you trying to understand how a 30 dB hearing protector can protect your hearing against the 150 dB sound of a gunshot?
Are you trying to find the best ear plugs for protection against water? (And wind?)
Are you trying to reduce the wind noise while riding a motorcycle?