The NEO is a one-size-fits-most hearing aid. It measures 0.5" in diameter and 0.875" in length.
The hearing aids are shaped specifically for either the right or left ear canal. They are marked with an R for your right ear and an L for your left ear.
The hearing aids come assembled with medium bell domes for your comfort. If these do not work for you, we also provide small and large sized bell domes in your MDHearing box.