Pbo 7A Opaque Markers are professional-quality markers suitable for most textilesthin or thick, dark or light. Shake well for a few seconds before use. Store flat.Tip: All colours can be fixed by ironing on the reverse side of the fabric for 5 minutes (without steam setting), after allowing the application to air dry for 2 hours. Once fixed, colours will hold when hand washed or machine washed at up to 40C.