Check the listing for details. Filter Sock 200 Micron Welded (4" x 12") - Seachem. Condition: New. Listed at 7.26 USD. Filter socks are a critical component in maintaining water quality in aquariums. They remove suspended debris and detritus, which often lead to excess dissolved organics, nitrate, and phosphate when left unchecked. This makes Seachem Filter Socks an integral addition to any sump and overflow system. Seachem Filter Socks feature durable, welded seams and have a singed finish, which reduces wear and prevents release of fibers back into the water column. In addition to a 100 micron rating for exceptional particulate removal, they feature welded seams, which, unlike threaded seams of similar products, will not breakdown over time. They have a singed finish, which reduces wear and prevents release of fibers back into the water column. Finally, the plastic collar simplifies installation and easily fits standard sump fittings. Small: 10 x 30 cm / 4” x 12” (10 cm / 4” plastic collar) Large: 17.5 x 40.5 cm / 7” x 16” (17.5 cm / 7” plastic collar) Listing and template services provided by inkFrog