EZ-Mark harness crayons are a great way to identify if a ewe or doe has been bred. For best results, use in outside temperatures from 40–80°F. Crayons are compatible with Premier’s Deluxe Marking Harness, Nylon Breeding Harness or Cross Your Heart Leather Breeding Harness. (Harnesses sold separately.) Size: 4" length x (Front: 2" width, Back: 2 1/4" width) x 1" height Contains wax, colorants and inert excipients; no toxic components Metal cotter pin (hidden under the label) comes with each crayon Plastic case protects crayons during transport. Remove protective plastic case before use. Change crayon color every two weeks to narrow down if/when an animal was bred, or re-bred. The shade of the marks on wool may not exactly match the crayon color. EZ-Mark harness crayons are a great way to identify if a ewe or doe has been bred. Crayons are available in red, blue, green, orange, yellow and black. For best results, use in outside temperatures from 40–80°F. Crayons are compatible with Premier’s Deluxe Marking Harness, Nylon Breeding Harness or Cross Your Heart Leather Breeding Harness. (Harnesses sold separately.)