Seachem The Bag is a unique polyethylene filter media bag that allows fishkeepers to customize the types of media that they choose to put into their filters. This welded filter bag is incredibly durable and unlike stitched seamed bags is completely resistant to bleach, caustics and acids. The fine, 180 micron mesh comes with a convenient locking mechanism that ensures your media is secured within the bag itself. The bag is 5" x 9.5" in size and is well suited for nearly every type of media on the market, giving aquarium owners the flexibility and freedom to use the products they need, and not the ones they don't. Be careful not to overfill the bag to the point of ripping or tearing. 9.5" x 5"