(Sergeant's) Natural Defense Squeeze-On for Dogs provides safe all-natural flea, tick and mosquito control for dogs and puppies. Natural Defense attacks a neurotransmitter found only in insects, causing a complete breakdown of the central nervous system and nearly instantaneous death. Formula includes oils of clove, peppermint, cinnamon, lemon grass and thyme. Kills and repels fleas, ticks and mosquitoes for up to four weeks. Do not use on puppies less than 12 weeks of age.