here is advice from Earasers:

This successfully meets Flare’s design objective

medical-grade polymer that's soft

Excellent protection

Noise Reduction Rating (NRR) – 26 decibels

EARasers Hi-Fi Reusable Ear Plugs For Dentists And Hygienists Size:Small here is advice from Earasers:EARasers Hi Fi Dentist and Hygienist Ear Plugs are the first hearing protection solution to really address the unique hearing protection needs of dentists and dental hygienists. For a long time now, NIOSH (the National Institute for Occupational Safety and Health) has recognized noise induced hearing loss as the most common occupational injury, and yet very few good solutions have been found to protect dental professionals. Enter EARasers Hi Fi