Shipping is slow as described. Works well. We live in south USA with heavy tick population. After treatment, no fleas do find rare stuck tick dead or acting weird. Occasionally new arrival in the hair. I believe ticks have to bite your dog before dying with a chewable. Do not believe they emit anything. Our dogs routinely lose collars so have not tried Serestp collar. Price is about half of what you would pay in store. Do not believe you can safely buy large dog dose and cut in half for smaller dogs. No guarantee media is evenly distributed. Unfortunate as we have 12 dogs.