Uni liquid chalk markers utilise water-based pigment ink so you can mark on windows, glass, mirrors, plastic and metal surfaces with ease. The ink won’t wash off in the rain, yet is easy to remove with a damp cloth. For permanent application the markers can also be used on chalkboards for a bold statement. Each marker features a bullet nib so it's easy to write. The markers are ideal for signage and can be used indoor and outdoor. The ink is made using a water-based formula and each colour is vibrant and opaque. Each marker has a round barrel that's comfortable to hold. Your markings will be permanent on chalkboards, but can be easily wiped off glass and metal surfaces. The cap colour of each marker matches the ink colour to help you find the right pen. There are 4 markers included in this set in different colours. The ink is removable on non-porous surfaces.