The Ear Gear Original is designed to fit hearing instruments from 1.25-2 inches. Ear Gear Original fits most hearing instruments that use a size 13 battery. The Ear Gear FM is designed to fit hearing instruments from 2-3 inches and for those people using FM attachments. Ear Gear FM is also used to fit hearing instruments for people with sever hearing loss. Many of these instruments use a 675 battery. Simple, easy-to-use protection from dirt, moisture and loss Snap locking clothing clip with stretch cord Durable, will stand up to repeated washings Both styles are available with or without cord and in monaural or binaural models Available in a variety of fun colors including camouflage, gray, beige, red/orange, black, royal blue, pink/purple, chocolate brown