Approvals / Standards: ANSI S3.19-1974 CSA Class A Product_x000D_ _x000D_ Features_x000D_ - Earmuffs with NRR 28 dBA_x000D_ - For use with MSA slotted cap-style helmets_x000D_ - For use in high-noise environments, such as paper mills, foundries, mines and airports_x000D_ - Cups are sized and shaped to provide space for most ear sizes_x000D_ - Ergonomical leaning design_x000D_ - Comfortable large muff_x000D_ - Acoustic air tightness improves safety