The Lite Air Filter provides advanced protection against harmful particles in the air. The multi-layer filter technology is tested at the Research Institutes of Sweden (RISE) with results showing 98% filtering efficiency against particles down to 0.3μm in size. Each filter may be used for up to 100 hours or approximately 2 weeks, depending on usage. The filter is available in 4 sizes and each filter pack contains 3 replaceable filters.