Liberty 50 Plus IGR Spot On For Small Dog 600553 For dogs 33 lbs or less For use on small dogs over 12 weeks of age Kills 5 different kinds of pests on dogs including fleas, ticks, mosquitoes, lice, and mites Kills, repels, and prevents reinfestation of fleas for up to 5 weeks Kills flea eggs and larvae for up to 8 weeks