Package contains two black coarse filter sponges (one with a strainer inside). The strainer inside the one sponge will fit 1/2 in. Uplift tubes and 1/2 in. Tubing. Fits: maxi-jet pumps, maxi-jet power heads, visi-jet protein skimmers, visi-jet pumps, seaclone protein skimmer, quicksand bio filters and will fit most aquariums pumps.