Liberty 50 with sunlight-stable Nylar IGR kills more Fleas, Ticks, Mosquitoes, Lice and Mites than leading Spot-on treatments! Liberty 50 not only kills, but repels and prevents re-infestation of pests for up to 8 weeks. Liberty's active, Permethrin is known to be one of the safest on the market - in fact if you check any of the Spot-On Websites, you won't find Liberty 50 listed as having any negative reactions. 3 month supply At 1/2 the price then other flea & tick spot-on treatments! Kills, repels and prevents re-infestation of Fleas for up to 5 weeks. Kills Flea eggs and Flea larvae for up to 8 weeks. Breaks the flea life cycle. Kills, repels and prevents re-infestation of Tick for up to 6 weeks. Kills or repels Mosquitoes, Lice and Mites on dogs for up to 4 weeks. Active Ingredients: Permethrin.........50% Pyriproxyfen......1.20% Other Ingredients:.....48.80% DO NOT USE ON CATS.