Upon completion of the Roving elves quest you may be given a Crystal Bow 2/10 (500 shots). This bow is sung from crystal by the Elves of Tirannwn and has the power of a magic shortbow firing rune arrows with the special attack. It requires level 70 ranged and 50 agility to equip. If you wish to recharge it speak to Islwyn in Isafdar.