Specialist Crafts Spectrum Permanent Markers are long lasting and are permanent on most surfaces. The quick-drying black ink is non-toxic and xylene-free. The generous nib can create marks from 0.5-2mm wide making this a versatile marker pen. Tried and tested by Graphic Design Teachers and our Creative Team, all came back with excellent results. The quality of other educational brands, at sensible prices. Pack of 48 comes in a handy multi-use tub.