A Regular or Receiver mold is generally used to mount the receiver of a body-worn aid, but can also couple to a BTE aid through a polyethylene adapter for economy or allergy reasons. A variation includes tubing, either cemented or otherwise held in place with one of the locking devices. This style can normally be manufactured in any material or combination.
The Skeleton is a popular style because it leaves an open space in the concha to enhance appearance. It can be made from most materials and accommodate most acoustic options, and can be cut down by the dispenser into other styles if necessary. A variation is the Semi-Skeleton, which has much of the outer rim of the concha removed to facilitate insertion in cases of reduced dexterity or extremely hard ear texture.
The Canal mold was once used for only the mildest losses, as it reproduces just the canal portion of the impression. Today, modern canal molds made from soft silicone are extremely effective in controlling feedback when using very powerful BTE hearing aids. A long canal is essential in this application.
Canal-lok molds provide more retention than canal molds (except those made of soft silicone), through a projection along the bottom of the concha. The projection also makes this earmold style easy to insert and remove. A variation adds a helix for additional retention without sacrificing the cosmetics of the style.
The Shell mold provides a good acoustic seal because it covers the concha's surface, and it is often used with moderate- and high-gain hearing aids. A variant includes a flap covering the tragus for feedback inhibition.
A Half-Shell style is recommended for patients with reduced dexterity, since the top half of the earmold is omitted. When made from soft silicone, it provides a slightly broader acoustic seal than the canal style.