Helmet attachment. Slot attachment with quick mounting without tools. Working, airing or park position. Attachment for visor. Extra noise muffling for both low and high frequencies, intended for noise with especially high noise levels. A double-shell minimizes resonance in the holder casing. High frequency attenuation is maximized while 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. Otherwise see adapter table for helmets to protect the directory. Complies with PPE directive 89/686 / EEC and applicable sections of European Standard EN 352. attenuation values Frequency Hz 63 125 250 500 1000 2000 3150 4000 6300 8000 Average (dB) 20.1 17.1 24.5 34.8 40.2 39.6 38.2 46.7 45.9 43.1 Std. Deviation (DB) 3.3 2.3 2.8 2.2 2.0 1.8 3.8 4.2 3.1 2.5 Acq. dämpn. (DB) 16.8 14.8 21.7 32.6 38.2 37.8 34.3 42.5 42.8 40.6 H M L SNR 40 32 22 34
TISSU : noir