Silverhawk feathers

Silverhawk feathers are tradable items won on Treasure Hunter used to charge Silverhawk boots. 500 of the feathers are required to charge the boots, which then gives the boots 500 charges.

Trivia

 * The item was made available on the Grand Exchange on 10 March 2014, 4 days before it was officially released.
 * After its initial promotion, the cash out value was made 10x higher.