Buy RS3 Fungal bowstring
The Fungal bowstring is a stackable bowstring in RuneScape 3. It works just like a regular bowstring, but it stacks in your backpack. This makes it a great pick for stringing lots of bows in one long session, since you do not need to keep filling your inventory with single strings.
You can use it to string many bows, from regular logs up to elder logs. It works on shortbows, shieldbows, the comp ogre bow, and the eternal magic shortbow. It is a members-only item, it is tradeable, and it weighs nothing.
Players make this item by spinning five tempered fungal shafts at a spinning wheel. Making one needs level 82 Fletching and gives 75.2 Fletching experience. A seer's headband 2 or higher lets you spin them 33% faster at the Seers' Village spinning wheel. There is also an achievement called "A Fungal Fun Ghoul" for spinning one at the wheel in the City of Um.
If you train Fletching and want an easier way to string big batches of bows, the Fungal bowstring saves space and time. Its examine text sums it up with a joke: "Unlike regular bowstrings, they leave mush room in your backpack."