Supplies of the best quality of these disappeared around the second world war never to return. The modern product is regarded as inferior to that formerly hand gathered by family groups in Siberia, Manchuria, and parts of Eastern Europe. Only the long bristles along the spine are suitable for brush making. The bristle has natural curve and the end has split ends that are referred to as a flag. Poor quality bristle brushes are trimmed and lose the flag, but the best brushes are made by craftspeople who are able to sort and arrange the bristles so the curve is inward and the flags are preserved.