These soft and flexible earplugs are made from a unique polyurethane foam developed by Sony. This means they adhere better to the ear canal, improving sound insulation and blocking out more noise - especially in the high frequency range. The combination of elastic and foam materials and the newly developed shape reduce pressure on the ear and make these earplugs extremely comfortable to wear. They are also easy to clean. There are four different sizes available, so you are guaranteed to find the perfect fit for the size and shape of your ears.Do not use water, wet wipes or organic solvents such as alcohol to clean your sound-insulating earplugs, as this can shorten their lifespan prematurely. If there is foreign matter such as earwax on the mesh of the earplug, the sound will be muffled or difficult to hear. Remove the earbud from the headset and run a cotton bud gently and slowly over the mesh to remove the dirt. Please take care not to tear the mesh fabric.