Six plant oils. Citronella, cedar, lemongrass, peppermint, geranium, and rosemary. That is the whole formulation. No pesticides, no synthetic compounds, no preservatives, no fillers. The oils are sealed inside a controlled release housing the size of a coin.
Linda actually opened her phone and looked the oils up while I sat there. Each one has a long history of repelling ticks and fleas in nature. Together, in the calibrated blend the Tag uses, they are dramatically more effective than any one of them alone.