An authentic 100% boar's bristle brush will contain 100% natural brisle from the wild boar usually found in India, China or the Far East. The highest quality Boar Bristle brushes are made from carefully pretreated bristles that are soaked to remove the aroma of the boar. Lesser quality brushes are made with bristles that are not presoaked, which explains why some boar bristle brushes will give off an "aroma" when they become wet. Mason Pearson and Kent boar bristle brushes are famous for using "pretreated and presoaked" bristles to prevent any lingering aroma from the bristles.