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. Black Pack of 48 comes in a handy multi-use tub.