SureFire Sonic Defenders Plus Filtered Flanged Earplugs Ear Lock by SureFire retention ring utilizes seven contact points to lock earpiece in place and fit the same way every time 24dB Noise Reduction Rating (NRR) with filter caps inserted Lowers potentially dangerous noise levels above 85dB Hear safe sound levels (with filter caps out) as if you weren't wearing ear plugs Made from hypoallergenic, medical-grade polymer that's soft, durable and long-lasting Ear Lock by SureFire retention ring utilizes seven contact points to lock earpiece in place and fit the same way every time