Check the listing for details. Filter King 18.5x21.5x1 Air Filter 4-PACK MERV 8 Actual Size 18.5 x 21.5 x .75". Condition: New. Listed at 49.99 USD. FILTER: This is a MERV 8 rated 4 pack Air Conditioner Filter | Size: 18.5" x 21.5" x 1" - Actual Size: 18.5" x 21.5" x .75" | MADE IN USA: Fully manufactured in the United States. Made from the highest quality materials and construction. (EPA Establishment Number: 103501-FL-1) | MAX PERFORMANCE: Our filters can last up to 90 DAYS before needing replacement. We do recommend to change your home air filter every 30 - 90 days for 1 inch filters. This will help maintain the longevity of the intended application like A/C and heaters | CAPTURE MORE: Protect your home! The pleated design captures more particles and extends lifetime of the filter. Merv Filters trap airborne particles without impacting air flow. Feel the difference in 48 hours. | FAST & EASY INSTALLATION: Open, Slide and Close! A simple yet effective replacement air filter for your home.