One of the best purchases I've ever made. Cannot believe I've spent money and wasted time on any other flea/tick meds. Bite the bullet and buy this collar, you won't regret it.  I've seen ZERO fleas ever since the first collar I bought 2 years ago and what little ticks I do see on my beagle (who hunts and is outside/in the woods quite a bit) are dead.  Really took the worry out of flea and tick season for good!