3M™ Peltor™ Optime™ 105 behind-the-head earmuffs features low-profile earcups that fit well with most helmets, Feature double-shell technology for effective hearing protection. Benefits •Patented Twin-Cup™ design has soft, foam-filled earmuff cushions. •Behind the head design allows for easy use with hard hats. •Liquid/foam filled earmuff cushions. •Color-coding for compliance sighting. •Noise Reduction Rating (NRR)*: 29 dB. CSA Class AL