Twin-Headed Greatbow | Dark Souls 2 Wiki

Parameter Bonus: Strength, Dexterity,Magic, Fire, Lightning and Dark bonuses - The scaling multiplier applied to the [Attack: stat]. Scaling quality is from highest to lowest as follows: S/A/B/C/D/E.
The higher the player's [Str, Dex, Mag, Fire, Light] stat, the higher the [Attack Bonus: Stat] is (found on the player status screen). The higher the scaling letter, the higher the percent multiplier applied to the [Attack: Stat].
This resulting bonus damage is added to the base physical damage of the weapon and is shown in the equipment screen in blue numbers as a "+ X".
Durability: The weapon's HP, when the durability hits 0, the effectiveness of its attacks become weakened to the point of almost uselessness. When an items durability is low, a message will come up saying "Weapon At Risk!" at this point the weapon does not perform at it's best.
Weight: How much the item weights when equipped.
Stability: How well the player keeps stance after being hit
Attack Type: Defines what kind of swing set the weapon has.
Regular(R), Thrust(T), Slash(Sl), Strike(St)