10 STKS Aquarium Filter Zakken Herbruikbare Polyester Mesh Aquarium Filter Zak Aquarium Media Mesh Filter Zakken met Rits Isolatie Zakken(wit)

... these are large bags, around A4 or so—more than twice the size of my not-small external filter. I wanted a bag for carbon use now and again and one for crushed seashells, as I have very soft water. I have folded one of the bags less than half and then some from the top is folded too. It fits OK, I guess. Don't be an eejit like me and assume suitable sizing. Check the measurements. That aside, the bags are Ok, do the job and are cheap.