Molded cartridges have a fibrous structure that provides depth filtration by using a gradient density depth filter. These filters are capable of capturing a wide variety of different sized particles. Molded cartridges rely on the depth of the filters to gradually filter out the unwanted particles and sediment. Particles are retained and become trapped in the matrix of the media, a permeable material used to separate suspended particles from liquid.

Molded Polypropylene: These cartridges are also known as spun-wound cartridges and have a fibrous structure that provides depth filtration by using a gradient density depth filter. The fibers are locked in place with a thermoplastic binder. Annular (ringed) grooves are used to increase dirt loading capacity. This cartridge is produced without a center support core.

Molded Cellulose/melamine resin: Like molded polypropylene, this cartridge is produced without a center support core. It has a fibrous structure manufactured using a felting process to generate a gradient density depth filter. The fibers are locked in place with a thermoplastic binder. Annular (ringed) grooves are used to increase dirt loading capacity.