Pleated - Pleated Heavy Paper for fine particles: 14 Merv Rating, Traps & Holds 95% or better of particles 3.0-10 micron and 85% of 0.3-1.0 micron

Polyester - 100% Polyester on both sides for coarser particles: 8 Merv Rating, Traps & Holds 70%- 85% of particles 3.0-10 micron

Charcoal - 2-Sided Carbon and Polyester on other side for fine to medium particles: 13 Merv Rating, Traps & Holds 90% or better of particles 3.0-10 micron and less than 75% of 0.3-1.0 micron