Princeton Artist Brush Neptune Series 4750 – 4-Piece Synthetic Squirrel Watercolor Paint Brush Set- Includes Aquarelle ¾” Oval Wash ½ & 2 Round Brushes Sizes 4 & 12. Soft & Supple Design – Each watercolor brush is designed with a beautiful blend of silky smooth synthetic hair that’s as soft and supple as natural squirrel.