These Bohin chalk cartridges not only perform precise line marking, but are also capable of exact point marking. They can be used on a wide range of surfaces and mediums, such as: textiles, wood, paper and plastic. They can also be used for patterns and stencils in hobbies, sewing, quilting, model building and more! The chalk cartridges are easy to change out when worn out, and the pencil holds them tight so they don’t slip while you are using them. The markings wash out without a trace, even after ironing, or they can be erased with a fabric eraser!