These earplugs are made of pliable foam that can be rolled between the finger and thumb prior to insertion in the ear. Once in place, the earplugs slowly expand to comfortably fill the opening of the ear. They block out about 29 decibels of sound, which does not interfere with the ability
to hear conversational speech at a normal loudness level with a nearby speaker such as a teacher.   It does, however, block out some of the background noises that are so distracting for individuals who have difficulty screening out irrelevant sounds.