These Richeson pure bristle “Signature” brushes come in a set of 5 (Round size 4, Fan size 4, Bright size 2, and Flat sizes 2 and 4) and are designed with an innovative interlocking system. The fibers in the brushes are designed to interlock to maintain the shape of the brush through repeated uses. This makes the brush easier to work with. Professional and new artists alike appreciate these brushes for how easy they are to use. Bristle brushes are where painting began, and these brushes are made with the highest workmanship and are made with the highest quality raw materials assembled by skilled craftspeople.