So far, the Seresto collar is doing what it is supposed to do. I put it on Wolfy in April, and NO fleas or ticks to be found on him. I like this method so much better than the once per month topicals, and I'm glad I decided to give it a try. This collar will carry him thru December, and I probably won't go with a new one till next Spring again, unless the winter is unusually warmer than normal. I would recommend this method of pest control/prevention, 100%.