Pro Arte Renaissance Squirrel Mop Watercolor Brushes use a high quality hair that holds a huge amount of color while retaining a sharp point. A unique feature of squirrel hair is its ability to hold huge amounts of color, which is ideal for watercolor artists working on a large scale. By the use of traditional three-knot 'quill' binding, Pro Arte are able to pack this particularly fine hair tightly enough to create a brush which gives a superb belly and provides a long, useful life.