Russian Sable Brushes are made from the tail hair of the Russian Sable. This material offers an ultra-fine tip. Russian Sable hair is about 1/4 the diameter or smaller compared to a human hair. It is a soft material that is excellent for producing ultra-fine lines. The shorter bristle lengths are awesome for Calligraphy and lettering and the longer bristle lengths are great for general applications where fine detail is desired.