Berserker helm

 The Berserker Helm is a helmet that requires 45 Defence and completion of The Fremennik Trials to wear. It is commonly used for its Defence stats which are roughly equivalent of a Rune Full Helm, and for it being one of the few helmets in the game to add a Strength bonus, with +3. It can be bought from Skulgrimen in Rellekka for 78,000 coins.