Sable/Kolinsky Brushes are not really made from sable hair at all. The hair comes from the tail of a species of mink that is a member of the weasel family, and is found in Siberia and northeastern China. Because of its strength, spring, and ability to retain shape ("snap"), it is considered the finest fiber for watercolor and oil brushes. It holds a very fine point or edge. Kolinsky is considered to be a professional grade of hair, and if properly cared for, it will last for many years.
A quality pure red sable brush is a good alternative to the more expensive Kolinsky, with similar performance and durability.