Seachem The Bag is a ground-breaking welded filter bag with a resilient non-stitched seam. It has a 180 micron mesh, is resistant to bleach, caustics, and acids, and comes with a convenient resalable locking closure. It is available in a handy 5" x 10" size. It is perfect for all filtration products and has a remarkably long life. Welded seams, unlike the common stitched seams, are not subject to degradation from contact with bleach, caustics, acids, or other harsh environmental exposure likely to occur throughout regeneration of filter media. It is important to be careful not to overfill or over-pack, as welded seams can be forced to detach by excessive pulling forces. Directions Place the desired filtration material e.g. Purigen, CupriSorb, etc. and close The Bag using the resalable locking closure. For the best results, The Bag should be placed in an area which maximizes the flow of water through it.