{"product_id":"21-1-2x21-1-2x1-air-filter","title":"21 1\/2x21 1\/2x1 Aerostar Air Filter","description":"At a true 21 1\/2\" x 21 1\/2\" x 3\/4\", the 21 1\/2 x 21 1\/2 x 1 Aerostar fits a nominal opening that measures the same in both nominal and actual dimensions - unusual in the filter industry. This is a custom-spec size used in certain regional HVAC markets. MERV 8 handles standard residential dust and pollen filtration. MERV 11 covers pet households and most common allergen concerns. MERV 13 captures fine particulates including smoke, bacteria, and virus-carrying droplets - the grade for households with respiratory issues or in wildfire-affected regions. Pleated synthetic media with an electrostatic charge built into the fibers does the work. The pleats give you substantially more surface area than a flat fiberglass filter at the same nominal size, which extends the service life to a 60-to-90-day window under typical residential conditions. The electrostatic charge catches sub-micron particles where the physical weave alone reaches its limits. Manufactured by Con-Air Industries in Orlando, Florida. Cardboard frame, reinforced to maintain shape under blower suction. Custom-size returns benefit from precise dimensional matching - this filter is built to the OEM specification without modification, which is what prevents the air bypass gaps that defeat higher MERV grades.","brand":"Aerostar","offers":[{"title":"MERV 8 \/ 6","offer_id":41902207598746,"sku":"P80S.0121H21H-6","price":85.02,"currency_code":"USD","in_stock":true},{"title":"MERV 11 \/ 2","offer_id":41902207434906,"sku":"P15S.0121H21H-2","price":46.54,"currency_code":"USD","in_stock":true},{"title":"MERV 13 \/ 2","offer_id":41902207467674,"sku":"P25S.0121H21H-2","price":24.99,"currency_code":"USD","in_stock":true},{"title":"MERV 8 \/ 4","offer_id":41902207500442,"sku":"P80S.0121H21H-4","price":59.6,"currency_code":"USD","in_stock":true},{"title":"MERV 11 \/ 4","offer_id":41902207533210,"sku":"P15S.0121H21H-4","price":89.4,"currency_code":"USD","in_stock":true},{"title":"MERV 13 \/ 4","offer_id":41902207565978,"sku":"P25S.0121H21H-4","price":39.41,"currency_code":"USD","in_stock":true},{"title":"MERV 8 \/ 2","offer_id":41902207402138,"sku":"P80S.0121H21H-2","price":40.94,"currency_code":"USD","in_stock":true},{"title":"MERV 11 \/ 6","offer_id":41902207631514,"sku":"P15S.0121H21H-6","price":124.14,"currency_code":"USD","in_stock":true},{"title":"MERV 13 \/ 6","offer_id":41902207664282,"sku":"P25S.0121H21H-6","price":57.29,"currency_code":"USD","in_stock":true},{"title":"MERV 8 \/ 12","offer_id":41902207697050,"sku":"P80S.0121H21H-12","price":153.36,"currency_code":"USD","in_stock":true},{"title":"MERV 11 \/ 12","offer_id":41902207729818,"sku":"P15S.0121H21H-12","price":223.44,"currency_code":"USD","in_stock":true},{"title":"MERV 13 \/ 12","offer_id":41902207762586,"sku":"P25S.0121H21H-12","price":108.56,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0591\/6937\/4362\/files\/21Hx21Hx1_MERV8_1pk.png?v=1790041066","url":"https:\/\/aerostarairfilters.com\/products\/21-1-2x21-1-2x1-air-filter","provider":"Aerostar Air Filters","version":"1.0","type":"link"}