Which material is NOT commonly used for making earmolds?

Earmolds are typically created from materials that provide comfort, durability, and a good seal in the ear canal. Acrylic and silicone are two of the most common materials used because they can be easily molded to fit an individual's ear shape. Acrylic is hard and offers great clarity and durability, while silicone is softer, allowing for a more comfortable fit, especially for those who may experience irritation with harder materials.

PVC (polyvinyl chloride) is also utilized in some earmold designs. It has certain properties that can make it suitable for audiological devices because of its durability and flexibility, though it is less common than acrylic and silicone.

Conversely, fiber is not a standard or commonly used material for earmold production. While fiber may be used in various applications and industries, it does not possess the necessary properties required for earmolds in hearing aids, such as comfort and the ability to form a tight seal in the ear canal. Thus, it stands out as the least suitable option for making earmolds.