Avery Sound Company, Inc. offers the ultimate in comfort and sound quality with our custom molded earpieces. It works like this. We make an impression of the inside of your ear, which is then made into a plastic mold which slips into your ear. When properly fitted (and we GUARANTEE the fit), the earpiece will not fall out. Because the earpiece is placed inside the ear canal to deliver sound, hearing is drastically improved, and ambient noise is reduced.