2 Box of 2 (total of 4 bags) high quality, reusable aquarium filter bags Suitable as a holder for other mechanical or chemical aquarium filter media 225 micron thin-mesh aquarium filter bags are now used in Red Sea's Reefer and Max-S Systems 225 micron thin-mesh aquarium filter bags are perfect for whenever there is a lot of particulate matter in the water These 10.5-inch long aquarium filter bags for Red Sea's Reefer and Max-S aquariums will also fit any standard 4-inch filter bag holder you will receive 2 Box of 2 (total of 4 bags)