Features: Safety Helmet Mounted: easy to clip on a hard hat, and fits most hard hats. Sound Insulation: Designed with 2 layers of professional noise dampening foam, high sealing solid cup, the earmuffs has good sound insulation effect, no more bothering by noisy noise. Functional: a simple way to improve sleep quality, reduce noise damage to hearing, avoid noise interference and effectively improve work and study efficiency. Reliable Quality: ABS shell, 304 stainless steel headband, good resistance to corrosion, heat and oxidation. Ergonomic Design: soft good tightness ear cushion, comfortable to wear. Wide Application: for sleeping, shooting, in flight, factory, construction site, etc. Specifications: Material: ABS+nylon+SS+sponge NRR: 23dB SNR: 28dB Class 5 SLC (80): 29.5dB Item Size: 21 * 15cm / 8.27 * 5.91in Item Weight: 307 / 10.83oz Package Weight: 315g / 11.11oz Package Size: 20 * 14.5 * 9.5cm / 7.87 * 5.71 * 3.74in Package List: 1 * Ear Muffs