Tell pesky parasites to bug off with the Hartz UltraGuard Plus Flea & Tick Collar for Dogs & Puppies. This collar kills and repels both fleas and ticks on pups with necks up to 22 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. For continuous flea and tick protection from head to tail replace the collar every 7 months.