Unlike permanent markers and art markers, which can contain chemicals harmful to animals, Animal Marker use "legal pigments". These pigments are non-toxic and devoid of any hazardous materials. For use on the rodent's coat. Colour will not remain on the animal's skin. A single marker can be used to mark 300-500 animals (depending upon animal size and/or applied area). Once applied, colours remain for 6-12 weeks. Most suitable for animals with light coloured fur.