Package Contents: • 1 Urban Air Mask Skin • 2 Urban Air Filters • 2 Urban Air Valves • 1 Urban Head Strap • 1 Travel Pouch The mask uses a five-layer filter technology in order to provide a superior protection against different particle types and sizes. The multi-layer filter technology is tested at RISE R&D center in Sweden, one of the world’s most advanced filter laboratories, and consists of the following layers: Outside PP Layer - Outside filter wrapping in a durable finish Active Carbon Layer - Filters gases and reduces odor 1st Electro Charged Layer - Filters larger PM10, pollen and other allergens 2nd Electro Charged Layer - Filters smaller PM2.5, dust and bacteria Inside PP Layer - Inside filter wrapping with smooth and skin-friendly finish