It serves the same purpose as its Dark Souls counterpart; while wearing this ring, players have an increased chance to acquire rare items from defeated enemies. It is extremely useful against enemies with a high drop rate, but is useless against bosses, who have a fixed drop rate of specific items.
The regular ring can be found on a corpse on a lava filled cauldron hanging in the giant circular room in the Iron Keep. In order to get to it, the player must climb the ladder located in the platform room adjacent to Belfry Sol and climb another ladder to reach the top of the keep and then drop down some giant metal beams to reach the cauldron.
The +2 variation can be obtained from the Belfry Gargoyles in NG+ or in NG with the use of a Bonfire Ascetic at the Upper Ramparts bonfire, a Chaos Storm with a maxed Pyromancy Flame will make short work of them, even in NG+.