The L1H Cap Mount Leightning® Earmuff offers maximum protection with a contemporary design and now features Air Flow Control Technology. This muff can be used with a wide range of popular hard hats. The earcups snap in place during use and swing back when not in use. An adapter is included. The L1H Cap Mount Leightning® Earmuff has a NRR rating of 23. Sold in cases of 20 earmuffs.