Aerostar Pleated Air Filter, 13, 18x18x1, Pack of 6, Made in the

- Nominal size: 18x18x1; Actual size: 17 3/4"x17 3/4"x3/4"; This 13 filter is comparable with 1500-1900 & 10. - Aerostar filters are made with electrostatically charged synthetic material. - Protect your family and loved ones with clean indoor air quality at home. Aerostar filters are a simple to install and cost-effective step towards a healthier home environment. - 100% synthetic electrostatic media for high efficiency with low air flow resistance. For best results, change your filters every 60 to 90 days during normal times of year but increase frequency to 30 days during peak summer and winter months when your unit is working the hardest. - Aerostar filters are manufactured in the by Filtration Group, a world-leading manufacturer and supplier of filtration solutions for residential, commercial and industrial applications.