21 1/2" x 23 1/2" x 4" MERV 13 - Ultimate Allergen Reducing Pleated Air Filter - 6 Pack MERV 13 - Pleated Air Filter:21 1/2" x 23 1/2" x 4" MERV 13 - Pleated Air Filter MERV 11 pleated filters offer

MERV 11 pleated filters offer significantly higher particulate efficiency

10" x 33" x 1" MERV 8 - Premium Pleated Air Filter - 6 Pack

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

Actual Dimensions: 13 7/8" x 29 7/8" x 3/4"

Actual Dimensions: 19 7/8" x 19 7/8" x 3/4"

21 1/2" x 23 1/2" x 4" MERV 13 - Ultimate Allergen Reducing Pleated Air Filter - 6 Pack MERV 13 - Pleated Air Filter:21 1/2" x 23 1/2" x 4" MERV 13 - Pleated Air Filter MERV 11 pleated filters offer21 1 2" x 23 1 2" x 4" MERV 13 Pleated Air Filter 6 Pack Actual Dimensions: 21 1 2" x 23 1 2" x 3 3 4" Filtration Group's High Capacity MERV 13 air filter is made of 100% Synthetic Media which will not promote mold or bacteria growth and has the following features: MERV 13 Efficiency, LEED compliant, High Efficiency in 2" depth, Advanced media incorporating both charged fibers and traditional mechanical principles, 100% recycled paperboard frame, Easy