Wat can u get for these?

You use it to purchase other bracers. 

there are vendor rewards from some of the vendors on isle of Quele'danas...to get those rewards you have to trade the drop from a instance boss....those bosses are listed above and the chance of drop. Each of the drops correspond to trade type i.e. bracer of FP you trade for a bracer for your player type...help of FP trade for helm for your type etc. The epic vendor will show you only the type of armour your class can wear.. I.e if you play a hunter it will show hunter armour..but if you was to log an alt mage it would show what your mage would use not the hunter.