MODEL COMPATIBILITY: this Filter-Monster replacement filter is compatible with AirDoctor AD3000 and AD3500 Air Purifiers REPLACEMENT TIME: For best maintenance, replace the HEPA filter every 12 months, or more often depending on air quality and environmental factors DIMENSIONS: This HEPA Filter's approximate dimensions are- Length: 13.38 inches, Width- 1.5 inches, Height- 16.25 inches, Weight- 1.03 pounds HEPA FILTER: This filter pack includes 1 HEPA Filter 25 YEARS OF FILTER-MONSTER: Backed by over 25 years of expertise, Filter-Monster is committed to delivering filtration solutions that combine trusted performance, reliability, and value, giving you the confidence to breathe cleaner, healthier air every day. This Filter-Monster HEPA Filter is specifically designed for AirDoctor 3000 and 3500 air purifiers, providing powerful protection against airborne pollutants with its ability to capture 99.97% of particles as small as 0.3 microns. This single replacement HEPA filter helps maintain optimal performance and cleaner indoor air, ensuring your purifier continues to deliver fresh, breathable results. For best maintenance, replace the HEPA filter every 12 months, or more often depending on air quality and environmental factors, so your home stays consistently healthy and refreshed. Filter Monster brings over 25 years of expertise in delivering filtration solutions that help customers enjoy cleaner, healthier air with trusted performance, reliability, and value.