The button back is used to attach the ear tag to an animal's ear. An Allflex tag applicator is needed to apply the ear tag and button back to the animal. Choosing "Yes" to the Button Back option, when ordering most female tags, will add blank male button backs of the color and quantity of tag you choose. Male visual tags and female button backs can be purchased separately.
The pink tag combination, on the right, is the more common option used for tagging most livestock, including Deer. It features a female visual tag, and a male button back. The female button back is shown on the left, with a male visual tag.