These water-based chalkboard markers are the perfect solution to ordinary chalk! Since they have professional quality ink from Germany, they will not smudge. They write smoothly and effortlessly. It's like having a white pen for blackboards! This white pen for blackboards can be used on a variety of surfaces including chalkboards, plastics, metals, glass, and vinyl. However, they should always be tested first and should not be used with any other chalk media. The ink can be removed quite easily by using a damp cloth or paper towel. There are bold and chisel nibs which allow for both broad strokes and smaller details when using. These nibs are also very sturdy and will last outlast any other marker in comparison. This white pen for blackboards can also be used both indoors and outdoors so that you can take your designs to the next level!