What is an Allflex tag button back?

The button back is used to attach the female portion of the two-piece 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 image on the left, is the more commonly used option for tagging deer. It features a female visual tag with a male button back. The image on the right features a female button back with a male visual tag.