The Darwin Non-Valve boasts exclusive long-lasting filter technology designed by the British Ministry of Defence. Filtering out nearly 100% of all harmful air pollutants and viruses. Unique Lab tested British Military Filtration Technology filters almost 100% of pollution, gases, allergens, smog, and pollen Lightweight, breathable material Filters 99.6% of all viruses and 99.7% of bacteria Filters PM10, PM2.5, PM0.3 Lasts up to 340 hours of active use (3 – 6 months) Ideal for air travel, grocery shopping and crowded places Zero valve which results in limited ventilation so not advised for high intensity activities such as running, cycling or other sport. Adjustable ear loops with toggles for secure snug fit Presented in eco-friendly packaging for storage Head-straps and Nose-foam are included. Valve Deactivator is not included.