Looks like a carbon fibre floss cartridge. If you haven't used it in an aquarium already the activated carbon would be good to run to remove any copper from the tank that may have contaminated the water although the carbon normally only lasts 2 weeks so in the long run it wouldn't help much. Copper is deadly to invertebrates so you will need to test your tap water and be careful on ornament choice, you can check your water for a copper at your LFS. Cant really tell what is behind the floss which is holding the carbon in so not sure whether the particle size would provide adequate surface area for filtration to occur. Personally I would get an old photographic film canister or larger tub and fill with sponge and place the airline in the bottom to blow air through the sponge. You then need a couple of small holes in the top and bottom and you have just built a filter.