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A player wearing Third age warrior armour.

Third age armour is a members only group of armour that is only obtained through completing Level 3 Treasure trails, trading with other players or by buying in Grand Exchange. According to Paul Gower, the odds of getting a piece of Third Age armour from a Treasure Trail are very small. There are three types of armour, one for each combat class, and each class has a specific piece of armour specified for that class:

• Third age warrior armour (Melee) (shield)
• Third age mage armour (Magic) (amulet)
• Third age ranger armour (Ranged) (vambraces)

Third Age armour generally rose in price after its release until early 2008. At that point it was bought out in the Grand Exchange for months. Some merchants used the armour as a method to sell partyhats. However, the price eventually peaked and crashed. Since then, the price of third age armour has become more stable, although the ability of the price to be stable is impaired by the low trade volume and the infrequent price updates (they do not happen every day).