Sentry Natural Defense Natural Flea & Tick Squeeze-On for Dogs & Puppies kills fleas ticks and mosquitoes for up to four weeks yet its safe to use on your dog or puppy and around your family when applied as directed. Each carton contains three monthly applications that feature natural active ingredients such as peppermint oil cinnamon oil lemon grass oil and thyme oil.Feature. Weight - under 15 lbs.