Merv 8 Pleated Air Filter - 13 3/4" x 17 3/4" x 1" Quantity:12-pack and the greater the pressure

and the greater the pressure drop it creates

the more efficient a filter is at removing particles

the A+2000 uses stage loading

Instead of face loading (particles captured on the outer surface of the filter)

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

Merv 8 Pleated Air Filter - 13 3/4" x 17 3/4" x 1" Quantity:12-pack and the greater the pressureAny 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.