Warsong Battle Tabard

The Warsong Battle Tabard is worn by members of the Warsong Clan and soldiers of the Horde who have proven their prowess on the battlefields of Warsong Gulch.

Source
This item is a PvP reward, and can be purchased for 2,059 honor points from:
 * in Northern Barrens
 * in Orgrimmar
 * in Silvermoon City
 * in Undercity
 * in Thunder Bluff

Trivia
Previously, the banners and tabard of the Warsong Clan bore the symbols of the Black Tooth Grin Clan, which is somewhat similar to that of the Warsong Clan.