Penguin’s wound cartridge filters are manufactured using a high-speed, continuous wind process which creates a superior one-piece filter with hundreds of diamond-shaped tunnels that get progressively smaller from the outer diameter to the core. Finer particles are progressively trapped as fluid travels to the center of the filter allowing for much greater retention capacity than that which is associated with straight surface filter media of the same dimensions and porosity. There are wide choices of Porosities, Lengths, and Diameters along withs a wide selection of wind and core materials so you can select the appropriate combination for your filtration needs. Wind materials include standard, fibrillated, FDA and utility-grade polypropylene, natural cotton, bleached cotton, rayon, polyester, nylon, modacrylic, and heat-cleaned glass fiber. Core materials include polypropylene, tin-plated steel, 304 stainless steel, and 316 stainless steel.