Designed for Lennox type furnaces and other furnaces and central air conditioning units with hammock filter frames. Electrostatically charged to trap airborne particles that can cause allergy flareups. Attracts and captures particles like household dust, lint, dust mite debris, mold spores, pollen, pet dander and smoke. 28 times more efficient than ordinary hammock filters. Convenient "When to Change" removable reminder sticker included inside package. 6 months clean air performance under normal conditions. Not washable. Type: Hammock Electrostatic Material: Synthetic Size: 30 In. x 60 In. x 1 In. Rating: 1000 MPR Life of Product: 6 mo