SureFire EP4 Sonic Defender Plus will protect your hearing against Noise-Induced Hearing Loss (NIHL) without compromising your ability to hear routine sounds or conversations in noisy environments. Their triple-flanged-stem provides a Noise Reduction Rating (NRR) of 24 dB. Safe sound levels are allowed to pass through into the ear canal, while potentially harmful noises.Features: Provides a 24-dB Noise Reduction Rating (NRR) with filter caps inserted Lowers potentially dangerous noise levels above 85 dB Patented EarLock(R) retention rings utilize seven contact points to lock earpieces in place and fit the same way every time; soft, double-flanged stems provide secure seals and all-day comfort Made from hypoallergenic, medical-grade polymer that's soft, durable, and long-lasting Low-profile design for superior comfort when worn with a mask, helmet or hat, or while using a phone, headphones or supplemental hearing muffs Serve as earpieces for compatible radio communication systems Available in clear, black or orange Each set is packaged in a convenient carry case and includes a polymer lanyard Note: EP4 earpiece will not provide hearing protection if the noise-reducing filter is removed Note: Available in small (S), medium (M), and large (L). Proper size is based on the dimensions of your ear's concha bowl. Size Radio Comm System Compatibility: Thales Covert Security Harness; Harris Security Force Communication Set; Motorola Surveillance Kits; Tactical Command Industries Tactical Earpiece Products; Peltor Lightweight Systems-Hearplug; Silynx C4Ops Headset