Tell pesky parasites to ‘bug off’ with the Hartz UltraGuard Pro Reflective Flea & Tick Collar for Dogs & Puppies. This collar kills and repels both fleas and ticks on pups with necks up to 26 inches for 7 months, and also prevents flea eggs from hatching for over half the year - stopping the flea life cycle and inhibiting reinfestation. The water resistant design remains effective even after getting caught in the rain. Additionally, the Reflect-X Shield reflects direct light for up to 450 feet for an added dimension of nighttime safety. For continuous flea and tick protection from head to tail, replace the collar every 7 months. For use on puppies 12 weeks of age and older.