These Liquid Chalk Markers are great for non-permanent designs and decorations on non-porous surfaces e.g. Windows, Dark Boards, Glass & Mirrors.Chisel stroke with 4-15mm widths.Fluorescent colours visible under UV light.Opaque and odourless water-based liquid chalk.Wipe off Virtually all Non-porous surfaces using a damp cloth.Contains 1x White, 1x Neon Yellow, 1x Neon Orange, 1x Neon Pink and 1x Neon Green.To use, keep the lid on the Marker and shake well. On piece of scrap paper, pump the nib VERY gently until the ink starts to flow.