The following fitting charts are simply guidelines. Everyone's loss has to be examined on an individual basis, considering not just the hearing loss but lifestyle, budget, personal preferences, manual dexterity and other factors.
Terminology
Open Ear: A miniature BTE hearing aid that sends the sound into the ear through a hollow filament tube. It is called "Open Ear" because it only has a small universal tip at the end of the tubing, thereby leaving the ear canal "open." It does not use a custom tip, unless the loss is more severe.
RIC: Letters stand for "Receiver-In-Canal." The receiver is the "speaker." It is a miniature BTE like the Open Ear aid, but instead of a hollow tube, it has a wire with the speaker at the end, that you place in the ear canal.
BTE: Letters stand for "Behind-The-Ear." When you see the term BTE, that usually refers to the conventional BTE, which is larger and more powerful than an Open Ear or RIC. The BTE sends the sound from the aid through a soft rubber tube into your ear canal. They are most often used on more severe losses and require a custom earmold to hold the tubing in place.
Earmold: The earmold is a custom made piece of rubber or plastic (silicone or acrylic) that is made from a casting or "impression" of your ear. It fits your ear like a glove and holds the sound tube in your ear canal from a BTE.