Merv 11 Pleated Air Filter - 13 7/8" x 21 1/2" x 1" Quantity:12-pack The "Practical Pleat" contains over

The "Practical Pleat" contains over 500% greater surface area than a MERV 10 one-inch pleat

the "A+2000" brand Permanent Washable Electrostatic custom air filters are truly quality products

To find the size the old unit should have sizing information printed on it

the greater it's resistance to airflow

Merv 11 Pleated Air Filter - 13 7/8" x 21 1/2" x 1" Quantity:12-pack The "Practical Pleat" contains overAny Kind of Filter's Extended Surface Pleated Filters outperform ordinary furnace filters with medium efficiency and are designed for lower pressure drop, and long service life which reduces HVAC equipment maintenance and energy costs. A higher MERV rating means that the air filter that you are about to purchase possesses a higher amount impurity filtration ability than your ordinary filter.