Hexcrest

From Arigon Wikipedia

The hexcrest is a unique Slayer item that is dropped by jungle and ice strykewyrms. It requires 20 Magic and 20 Defence to equip. When worn while slaying, it boosts the player's Magic damage by 12.5% and Magic accuracy by 12.5%. The hexcrest can be combined with a slayer helmet and focus sight to produce a full slayer helm, which provides the bonuses from all its components. It can be combined with a Focus sigh to make a Full slayer helmet.