These POSCA PC-7M Poster Markers contain water-based pigments which can be blended when wet or overlaid when dry. Each marker has a bold bullet tip to produce thin lines on the point and thick, 4.5 mm lines. Plus, they can be used on a variety of surfaces making it a versatile writing tool. Each marker has a 4.5 mm bullet shaped nib which allows you to create bold markings and precise colouring. You can blend these markers when they are wet or overlay them when they are dry. The water-based pigment ink is permanent on porous surfaces but can be removed from glass. The markers have a round, easy to grip barrel. You can use it to mark on paper, metal, glass, fabric, minerals, canvas, ceramic, wood and plastic. The lid colours match the ink colour to help you find the right marker. This pack contains 4 markers in black and white. POSCA tips can be removed and washed by rinsing it under cold water or leaving it to soak overnight. The ball inside the barrel mixes the paint, giving an even consistency, while the cap provides a tight seal ensuring protection and longevity of the tip. The PC-7M is appreciated by both beginners and professionals for its broad bullet tip, enabling both precise colouring and large-scale precision work.