Abstract: An ear tag having a first button with an aperture, and a pin having a head and a heel is attached to the first button via engagement of the heel in the aperture. A second button is provided having an aperture for engaging the head of the pin. At least one of the buttons has an additional frangible ring adjacent one of the apertures through which the pin is introduced and by which the pin engages the appropriate button. As force is applied to the buttons in opposite directions the additional ring breaks making the re-connection of the two buttons impossible.