Void set with 3 helms

The void melee set grants the player a 10% bonus toward melee damage and accuracy. The void knight mace and void seal are not required for the bonus. It is of great benefit to training melee skills, but maximum strength gear gives more experience over time.

The void melee set grants the player a 10% bonus towards Ranged damage and Ranged accuracy. The void knight mace and void seal are not required for the bonus. It should be noted that while void knight armour significantly increases Ranged output against targets that are lacking in Defence, the substantial attack bonus provided by regular ranged armour makes the latter more effective against stronger opponents such as bosses.

The Void mage set gives a +45% magic accuracy. This typically provides less accuracy and defensive bonuses than Ahrim's robes. If wearing Elite Void Knight robes, the set gives an additional 2.5% increase to magic damage. 

The effective magic attack bonus can be calculated with 1.45x + 28.8, where x is the equipment bonus while wearing the Void mage set. For example, if you have a magic attack bonus of +16 while also wearing the Void mage set, it effectively becomes +52 when factoring in the set effect. While wearing several best-in-slot pieces of magical gear, the accuracy of the Void mage set can surpass Ahrim's robes with the same gear.