Product details:

Aprilaire 510 - 31" x 28" x 4" Clean Air Expandable Filter, MERV 11 The Aprilaire 510 is designed for geothermal systems and larger HVAC systems. With a MERV 11 rating the 510 will remove dust, pollen, mold spores, bacteria, and pet dander from your home, while also maintaining a clean system and lasting up to 12 months.