The Reins of the Spectral Tiger summon a Spectral Tiger rare mount.
This item comes from a special loot card from the Fires of Outland set of the World of Warcraft Trading Card Game. When you redeem the code from <The Black Flame>, the item will appear directly into your inventory, no purchase necessary.
The code also unlocks the option to purchase an epic version of this mount at level 40: Unlike other loot cards in WOW TCG sets 1 and 2, this loot item requires you to spend gold to acquire it. This is because the loot items are not supposed to affect gameplay by giving a player an advantage over another; thus, it merely unlocks the option to purchase a different mount rather than giving a free mount.
The odds of pulling a Spectral Tiger card out of a Fires of Outland TCG pack is around 1 out of 156, extremely rare. The first card sold on eBay for $2,000. Now, cards are going for $800-$1,000.