Buy RS3 Dragon bane off-hand longsword
The dragon bane off-hand longsword is a tier 79 melee weapon in RuneScape 3. It goes in your off-hand slot and uses the slash style. You need level 80 Attack to wield it. It is a members only item.
This sword is made by upgrading a bane off hand longsword + 4 with a draconic visage at an anvil. It has 1876 accuracy and 483.9 ability damage. That makes it a strong pick for dual wield melee builds. It can also be augmented, so you can add perks to it with Invention.
Note that the 25% bonus damage against dragons only works on the dragon bane longsword and the dragon bane 2h sword. The off-hand version does not add that bonus.
The weapon degrades over 50,000 charges of combat. When it breaks, it can be repaired. A full repair costs 400,000 coins at base price, and it costs less on an armour stand or whetstone. The cost scales with how damaged the sword is.
This item is tradeable and can be stored in the bank or in GIM storage. It pairs well with a main-hand bane weapon for a matched melee set.