Written and maintained by CASRAI Editorial Board
Last updated
General product information for laboratory and clinic staff, not medical or audiological advice. For hearing concerns, see a qualified clinician.
Short answer
Hearing protection comes in three main device types, according to NIOSH: earplugs (formable, pre-formed or custom), earmuffs, and canal caps. Earplugs sit in the ear canal, earmuffs completely surround the outer ear, and canal caps cover the entrance to the ear canals on a lightweight band. Fit matters as much as type, so the rating printed on a package does not by itself tell you how well a worker is protected.
What is hearing protection?
Hearing protection is personal protective equipment worn to reduce the noise reaching the ear. NIOSH, the US National Institute for Occupational Safety and Health, describes the device types an employer can provide in its page “Provide Hearing Protection” (NIOSH, checked 2026-10-30); the type descriptions below follow that page.
How does hearing protection work?
Each device puts a barrier between the noise and the ear. Earplugs do it inside the ear canal, earmuffs over the whole outer ear, and canal caps at the canal entrance. A barrier only works as designed when it is seated or sealed correctly, which is why NIOSH keeps returning to fit.
Hearing protection types
What is an earplug, and what are the earplug types?
NIOSH describes earplugs as devices that slide snugly into the ear canal, and names three kinds:
- Formable earplugs, such as foam, which expand to fit the contour of the canal.
- Pre-formed earplugs, which are already shaped to fit most ears.
- Custom earplugs, which use an impression of the worker’s ear to make a device uniquely fitted to that person.
Earmuffs
Earmuffs completely surround the outer ear and are held in place by a headband or attached to a hardhat.
Canal caps
Canal caps cover the entrance to the ear canals and are held in place by a lightweight band.
Comparison of types, in NIOSH’s own terms
The table restates only what the NIOSH page says about each type. It does not rank the types by attenuation, because NIOSH does not.
| Type | How NIOSH describes it | Trade-offs NIOSH names |
|---|---|---|
| Formable (foam) earplug | Expands to fit the contour of the canal | Lightweight and easy to store; may be harder to learn to fit correctly |
| Pre-formed earplug | Already shaped to fit most ears | Earplugs in general are often more comfortable than earmuffs in hot environments |
| Custom earplug | Made from an impression of the worker’s ear | More durable |
| Earmuff | Completely surrounds the outer ear | Often easier to fit properly; heavier and may be uncomfortable in warm places; more durable; can interfere with the fit of other head-worn protective equipment; cushions do not seal effectively in very cold environments |
| Canal cap | Covers the entrance to the ear canals, held by a lightweight band | Can interfere with the fit of other head-worn protective equipment |
Earplugs vs earmuffs
NIOSH frames the choice as a set of trade-offs, not a winner. Earplugs are lightweight and, in hot environments, often more comfortable. Earmuffs are often easier to fit properly, while earplugs may be harder to learn to fit correctly.
Where it matters for labs and clinics
Two points from NIOSH are easy to miss when reviewing what a lab or clinic stocks. First, head-worn gear changes the picture: earmuffs and canal caps can interfere with the fit of other protective equipment worn on the head. Second, noise-cancelling headsets are not automatically hearing protection: NIOSH says active noise cancellation should not be considered hearing protection unless labeled with a Noise Reduction Rating (NRR).
For what the NRR number means and how OSHA treats it, see Noise Reduction Rating (NRR) on earplugs. For related supply lists, see the occupational medicine clinic supply checklist and the workplace wellness clinic supply checklist.
Common misunderstandings
- “The label number is the protection I get.” NIOSH says the NRR on the packaging often does not reflect the actual protection provided for each worker, and that individual hearing protector fit testing is the way to check each worker’s protection.
- “A short demonstration fixes fit.” A 2024 NIOSH systematic review of fit-testing systems and training (three studies, 756 participants, foam and pre-molded earplugs) found that simple instructions accompanying fit testing did not significantly improve personal attenuation ratings compared with no instructions; more extensive instruction showed promise (NIOSH Science Bulletin, checked 2026-10-30).
- “Any headset with noise cancelling counts.” Only when it is labeled with an NRR, per NIOSH.
FAQ
What is hearing protection?
Personal protective equipment worn to reduce the noise reaching the ear; NIOSH lists earplugs, earmuffs and canal caps.
How does hearing protection work?
It places a barrier in the ear canal (earplugs), over the outer ear (earmuffs) or at the canal entrance (canal caps), and works as intended only when fitted correctly.
What is an earplug?
A device that slides snugly into the ear canal. NIOSH names formable (such as foam), pre-formed and custom earplugs.
What are the earplug types?
Formable, pre-formed and custom, as described above.
What is the difference between earplugs and earmuffs?
Earplugs go in the canal and are lightweight; earmuffs surround the outer ear, are often easier to fit properly, and are heavier. See the comparison table.
Sources
- NIOSH (CDC), “Provide Hearing Protection”: https://www.cdc.gov/niosh/noise/prevent/ppe.html, checked 2026-10-30.
- NIOSH Science Bulletin (2024), “Enhancing Workplace Safety: A Systematic Review of Hearing Protection Fit-Testing Systems and Training”: https://www.cdc.gov/niosh/bulletin/2024/hearing-protection-fit-testing.html, checked 2026-10-30.
