Check the listing for details. Filter King 20x21x1 Air Filter 6-PACK MERV 8 Actual Size 20 x 21 x .75". Condition: New. Listed at 54.94 USD. FILTER: This is a MERV 8 rated 6 pack Air Conditioner Filter | Size: 20" x 21" x 1" - Actual Size: 20" x 21" 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.