AMP Accessory
Ops-Core AMP NFMI Earplugs
Passive wireless earbuds for double hearing protection. Near Field Magnetic Induction technology receives audio from NFMI-enabled AMP earcups — no batteries, no charging, no Bluetooth. Insert the foam tips, put on the headset, press the mode-switch button, and the earplugs seamlessly integrate for clear comms + 3DHT with NRR boosted from 22 dB to 34 dB.
Protection Levels
| Configuration |
NRR |
SNR |
| With AMP Headset |
34 dB |
41 dB |
| Earplugs Alone |
30 dB |
38 dB |
How NFMI Works
NFMI transmitters inside the AMP earcups create a short-range magnetic field that couples to passive receivers in the earplugs. All audio — radio comms, 3D Hear-Through, and talk-through — is reproduced inside the ear canal. The earplugs contain no active electronics; the magnetic field carries the signal.
To activate: press the NFMI mode-switch button on the left earcup. A double-tone confirms the switch. Press again to return audio to the earcup speakers.
Key Specs
-
Weight: 7 grams per pair (with foam tips)
-
Battery: None — completely passive
-
Foam Tips: 3 sizes included — Standard, Slim, Large (Comply Foam)
Kit Contents
- NFMI Earplugs (pair)
- Comply Foam Tips — 3 sizes
- NFMI Earplug Case
⚠ NFMI-Enabled Headset Required. These earplugs only work with NFMI-version AMP headsets. Standard (non-NFMI) AMP headsets do not have the NFMI transmitter. If you press the mode button without earplugs inserted, you will hear no audio.
Combined Noise Protection Ratings
| Configuration |
NRR |
SNR |
H / M / L |
| With AMP Headset |
34 dB |
41 dB |
41 / 39 / 34 |
| With RAC Headset |
32 dB |
39 dB |
41 / 36 / 32 |
| Earplugs Alone |
30 dB |
38 dB |
38 / 35 / 31 |
NFMI earplugs require an NFMI-enabled headset (AMP or RAC). The Mode Switch button on the headset toggles between NFMI earplug and standard headset-only operation.
How NFMI Works
Near Field Magnetic Induction (NFMI) uses a short-range magnetic field to couple audio from the headset ear cups to the in-ear receiver — no wires, no batteries, no Bluetooth pairing. When the earplug is seated in the ear canal and the AMP ear cup closes over it, the magnetic coupling activates automatically. The result: double hearing protection (ear cup + in-ear seal) with full 3D Hear-Through and comms audio passed through to the earplug.
Battery impact: NFMI engagement reduces AMP battery life from ~120 hours to ~80 hours (lithium, 21°C). In the event of battery loss, 3DHT powers down but the earplug continues to provide passive hearing protection and standard comms audio.
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