BioTek Marine Nylon Filter Socks 7" x 12" filter socks are quite possible the best filter socks available anywhere. Made from a nylon material, these socks will last through dozens of cleanings. Your typical felt type filter socks have to be replaced after 3 or 4 uses. Some aquarists wash felt type socks in the dishwasher or washing machine. The one time I tried the washing machine method it stunk up the laundry room and part of the house for a few days. Our BioTek Marine socks can be easily be washed out with a garden house or a sink with a decent amount of water pressure. We've even used them by filling them about 1/3 of the way up with carbon as an affordable way to run carbon without a separate carbon reactor.