These Solo Goya Masking Markers work like regular pump action markers, except that they dispense masking fluid! This masking fluid is non-toxic, quick drying, water-based and is easy to peel or rub off.The blue colour of the fluid makes it much easier to see on the working surface, than regular colourless masking fluid. Together, these features enable students and artists to have more control when masking.Remove from surface within two days of use.