Princeton has done it again. Almost 20 years ago, Princeton gave artists a synthetic version of sable that was almost the equal of fine Kolinsky and is still the standard for performance for its rivals. When we set out to create a synthetic version of squirrel we developed a brush that may actually outperform the natural version. Neptune is our thirstiest brush ever delivering oceans of color to the sheet. Experts in natural hair have been incredulous that this is actually synthetic.