The Isolation Series fittings are designed with a super soft memory foam that fits snugly into the ear canal, providing perfect comfort, a durable fit and excellent noise cancellation. The Isolation Plus (Tx) also features a special Wax-Guard coating that protects not only the memory foam ear tips, but also the earpiece, increasing the life of both. Its earwax-repellent properties prevent dirt from getting in, so nothing gets in the way of your music.