Insecticidal ear tags are molded plastic tags that are impregnated with insecticide that is released slowly onto the surface of the tag by diffusion.

'Grooming' activities by the cattle in response to the flies rubs the tags on the shoulder, back and flanks of cattle and helps spread the insecticide over the animal.

Studies have shown, Insecticide ear tags have provided excellent, long term control of horn flies and a reduction in face fly numbers.