For best results when using insecticide tags, it is recommended that you rotate among the chemical classes of tags yearly to reduce fly resistance to any one chemical class.
The Double Barrel Extra is actually a combination Organophosphate/Pyrethroid Insecticide tag while the Y-TEX XP820 offers a third chemical class called an Abamectin or the Avenger tags also offer a third chemical class called an Organochlorine.
