Liquid Chalk Markers by CHALKYPEN - Awesome fun for Kids - Safe and erasable water base - 6 mm reversible nib - Easy to use for both kids and adults - 10 colors premium quality satisfaction guarantee Value Pack10 Bright colors easy to use for both kids and adults Not messy dust free & easy wipe off. Chalky Pen are non-toxic, water base, low odor, acid free, child safe and long lasting. Great gift for children . These Liquid Chalk Markers have the best quality you can trust. USE On - Glossy board,Glass, Mirror. Windows. Metal. Led board and non-Porous surfaces. REVERSIBLE TIP - 6 mm Chisel tip easy to use for both fine and bold work.