Aquaculture filtration is a huge problem. Flowrates are high and the filtrate is delicate, slimy, organic and can easily become liquified, turning a solid waste problem into a liquid waste problem. Bag filters are very effective at removing organic particulate matter. The monofilament type is single-ply nylon resembling a piece of cloth or window screen. The felt type is polypropylene, thick and fluffy, giving it three-dimensional filtering ability. Both are washable, but wash the felt type gently. All bags are 32" long with a 7" diameter mouth and polypropylene ring that fits the optional Celcon® adapter (FBH) perfectly. Made in USA.