Behind-the-ear (BTE) hearing aids stay in place through a combination of the curved case resting over the top of your ear, an earhook or thin wire that follows the contour of your ear, and a tip (either a dome or custom earmold) that anchors inside your ear canal. No single part does all the work. The system distributes the weight across three contact points so the device feels secure without clamping down.
The Three-Point Contact System
The main body of a BTE hearing aid sits in the natural groove behind your ear, between the back of your outer ear and your skull. Modern devices weigh roughly 8 to 17 grams (less than a AAA battery), so gravity alone doesn’t pull them out of position. The curved shape of the case matches the curve of your ear, which acts like a shelf.
From the case, either a rigid earhook or a slim receiver wire loops over the top of your ear and drops down into the ear canal opening. This hook or wire creates the second anchor point: it presses lightly against the crest of your ear, holding the body of the device snug against your head. The third anchor is the piece that actually sits inside your ear, either a soft dome or a custom-molded earpiece. Together, these three points form a stable triangle that keeps everything locked in during normal movement.
How Domes Create a Friction Fit
If you have a receiver-in-canal (RIC) style BTE, the thin wire ends in a small silicone dome that tucks into your ear canal. Domes come in several shapes, and each one grips differently.
- Open domes have large vents that let natural sound pass through. They sit lightly in the canal and rely mostly on the wire’s curve for retention.
- Closed domes have few or no vents, creating a tighter seal against the canal walls. That seal adds friction and keeps the dome from sliding out.
- Power domes use a double or triple flange design, similar to the layered fins on foam earplugs. The multiple flanges grip the canal walls firmly, improving stability during movement and preventing sound from leaking out at high amplification levels.
Domes are available in multiple sizes, typically small, medium, and large. Getting the right size matters more than the style for day-to-day retention. A dome that’s too small won’t create enough contact with the canal walls, while one that’s too large will feel uncomfortable and may work its way out as your jaw moves.
Custom Earmolds for a Precise Fit
Traditional BTE hearing aids use a custom earmold instead of a dome. An audiologist takes an impression of your ear, and the mold is manufactured to match its exact contours. Because the shape is unique to you, the earmold locks into the natural ridges of your outer ear and canal like a puzzle piece.
Earmolds come in several designs depending on how much of the ear they fill. A “shell” mold covers the entire bowl of the outer ear and extends into the canal, offering maximum retention. A “skeleton” mold traces just the outer rim of the ear bowl plus the canal, leaving the center open to reduce bulk. A “canal lock” fills only the canal and wraps around half of the ear bowl’s rim, providing a middle ground between security and minimal visibility. For people who need the lightest possible fit, a canal-only mold sits entirely inside the ear canal with nothing visible in the outer ear.
Each design anchors against different anatomical landmarks. The concha rim (the inner ridge of your outer ear), the helix (the curled outer edge), and the heel (the notch between the small flaps at the front and bottom of your ear opening) all serve as natural locking points that prevent the mold from rotating or slipping out.
Why Material Matters for Grip
Custom earmolds are typically made from either acrylic or medical-grade silicone, and the two materials behave very differently against skin. Silicone is flexible and has a rubbery texture that grips skin on contact. That grip is exactly what keeps the mold from sliding, but it can also make silicone molds harder to insert, especially when new. Applying a small amount of water-based lubricant to the canal portion before inserting helps it glide in without sacrificing the grip once it’s seated.
Acrylic molds are rigid and smoother, so they slide in more easily but rely on their precise shape rather than friction to stay put. For people with very soft or loose ear tissue, acrylic often works better because silicone can grab the skin and push it around during insertion, making it difficult to achieve a snug fit. Your audiologist can also request a matte finish on a silicone mold, which reduces the initial grab while still maintaining good retention once it’s in place.
Sport Locks and Retention Accessories
If you’re active, running, or working out, a sport lock adds an extra layer of security. It’s a small, clear plastic “tail” that attaches to the end of the receiver wire, right where it enters your ear. The tail curls into the outer bowl of your ear, pressing against the concha to create one more anchor point. Sport locks are nearly invisible and easy to add or remove, so you can use them only when you need them.
Some people also use thin, flexible retention lines (similar to eyeglass straps) that clip to both hearing aids and loop behind the head or attach to clothing. These don’t help the aids stay on your ears, but they prevent a lost device if one does come loose during vigorous activity.
Wearing Hearing Aids With Glasses
Since both glasses and BTE hearing aids share the same real estate behind your ear, the order you put them on matters. Most people find it easier to put glasses on first, letting the temple arms settle naturally over the ears. Then position the hearing aid so its body sits alongside the glasses arm, not on top of it. Finally, insert the dome or earmold into the canal.
The hearing aid should rest close to your head rather than being pushed outward by the glasses arm. If the two keep competing for space, thinner-armed frames or a smaller BTE model can help. Some audiologists can also adjust the angle of the earhook so the device tucks in more tightly. When removing glasses, slide the arms straight back rather than lifting up, which avoids accidentally flicking the hearing aid off your ear.
Common Reasons They Feel Loose
A hearing aid that keeps slipping usually has a fixable cause. Ear canals change shape over time, especially after weight loss or as cartilage softens with age. A dome that fit perfectly a year ago may now be too small. Swapping to the next size up, or switching from an open dome to a closed one, often solves the problem immediately.
Sweat and moisture reduce friction, which is why hearing aids tend to feel less secure during hot weather or exercise. A sweatband worn under the device, or a moisture-resistant sleeve over the earmold, can restore grip. For custom earmolds, a refit every few years keeps the shape matched to your ear as it naturally changes. If your earmold has developed a smooth, worn surface over time, a replacement with fresh material will grip noticeably better.
Earwax buildup can also push a dome out of position. Keeping your ear canals clean helps the tip seat properly each time you insert it.