Manufacturer Part No: H540A-61-GB
The protection is based on a technology with a double casing that minimises resonance in the holder casing. This results in maximum high-frequency muffling, while at the same time its still easy to understand speech and signals.
An acoustic connection between the inner volume and the volume between the casings in its turn provides maximum low-frequency muffling.
The sealing rings are broad and filled with soft plastic foam for the best fit and low contact pressure.