The yellow SC2 earmuffs are suitable for environments with a medium to high level of noise (dB). The best choice in high frequency noise situations. Suitable for a wide variety of uses such as: building and construction, forestry use, industrial areas, production areas, agriculture, etc. The green SC1 earmuffs are used in general industrial work areas. Suitable for situations with a low to medium noise level (dB) and with medium to high frequency. The Orange SC3 earmuffs are indicated for use in low frequency noise situations. Suitable for extremely noisy environments such as: airports, car racing, while using pneumatic drills, etc. Attachment to the helmet with a bayonet adapter Universal 30 mm euro slot Performance differentiated by colour Smooth telescopic size regulation Non-conductive Certified for use with KASK helmet standards: CE EN 352 / ANSI S3.19 / CSA sizes: Universal size