(Fly Armor) Fly Armor attaches to horse gear to repel flies, gnats and mosquitoes. Fly Armor Browband holds 2 replaceable Citronella oil inserts (included) for up to four weeks of protection. Replace the inserts when they lose their effectiveness. Hook-and-loop attachments at each end allow you to fasten to your bridle or halter. Vaporguard backing provides a barrier between browband and your horse. 1 1/2" x 15". Two inserts.