These brush markers from Pentel contain the same strikingly opaque ink as the Pentel Milky Pop Pastel Gel Pen! High-quality nylon bristle tip is fine enough for detail calligraphy, and flexible enough for bold brush lettering. Opaque pastel ink shows up great on both dark and light papers. Water-based pigment ink can be layered for more intense color. Rear push system controls flow of ink.