$62.99 Aprilaire 413 Filter 2 Pack for Air Purifier Models 1410, 1610, 2410, 3410, 4400, Space-Gard 
Aprilaire 410 2410 1410 1610 1310 3410 Replacement Filter Alternative 1 Pack Box | eBay
Aprilaire 413 Filter Single Pack for Air Purifier Models 1410, 1610, 2410, 3410, 4400, Space 
