Ultra fit 340 R 4007 is a kind of earplug product under the brand of 3M. It is characterized by comfortable wearing, waterproof and dustproof, and can be used in multiple noise environments.
This manual explains how to correctly insert, fit, and verify the seal of the Ultra fit metal‑detectable earplug. It describes the proper insertion technique, how to perform a seal check by covering both ears with the palms, and the steps for safe removal to avoid ear‑drum injury.
The guide also covers routine cleaning with warm water or neutral soap, inspection for wear or damage, and provides the product’s acoustic performance data, including frequency‑specific attenuation values and an NRR of 25 dB. It notes the appropriate use of A‑ or C‑weighted noise levels for evaluating protection in different environments. This manual is written in Chinese.
| NRR | 25 dB |
|---|---|
| Average attenuation at 125 Hz | 28.5 dB |
Cover both ears with your palms and compare the external noise; if there is no difference, the earplug is sealed correctly.
Clean them regularly with warm water or neutral soap water and inspect for any wear or damage.
The earplug has a Noise Reduction Rating (NRR) of 25 dB.