Alen's standard medical-grade H13 Pure HEPA filter provides outstanding protection. It captures 99.99% of dust, allergens, and harmful fine pollutants as small as 0.1 microns. The air filter replacement lets you enjoy clean and healthy air every 30 minutes. You need a replacement air filter for an air purifier to enjoy a continuous clean air supply. Using the right air filter also extends the life of the Pure HEPA air purifier. The air purifier has a filter indicator light that tells you when a replacement air filter is required. After replacing the filter, reset the indicator light on the air purifier. Hold down the button until the light turns green. The package includes 1 BreatheSmart FIT50 (HEPA-Pure) Replacement Filter (Air purifier not included) and a medical Grade H13 True HEPA layer. Have that quality of the air you and your family deserves with Alen Air purifiers!