A custom fit hearing device that includes an in-ear housing designed to fit at least partially in a hearing device user's ear canal. The in-ear housing includes one or more areas on its outer-surface that are designed to provide retention of the in-ear housing in the ear canal. The one of more area may be rougher than the rest of the outer-surface of the in-ear housing, may have greater a friction coefficient than the rest of the outer-surface of the in-ear housing, may be made of a different material than the rest of the outer-surface of the in-ear housing, may contain granular material and/or may include surface features such as shapes extending outward from the outer-surface or undulations/ripples in the outer-surface. The in-ear housing may be produced using virtual designs and a 3D scan of the ear canal and may be manufactured using additive manufacturing or 3D printing.
