Disposable 3-layer NANO mask, breathability 200 l/m2/s, patented NANO fiber technology. Material bacterial filtration efficiency (BFE) ≥ 99.9%. Viral filtration efficiency (VFE) ≥ 99.9%, effectively filters particles of virus size. Protects against the spread of viral and bacterial infection with the filtration function of the material. Made in the Czech Republic. The recommended usage time is max. 12 hours. The product is intended for single use. Repeated use carries a risk of contamination and may result in reduced effectiveness. 50 pieces per package.