Flea collars are OK but best is Advantage or Comfortis . Comforits is a flea and heartworm protection which I use on my boys. It works better than Sentinal. Just my 2 cents.

Sorry, I miss spoke yesterday. Comfortis is a flea pill and Trifexis is the combination of heartworm prevention (Interceptor) and Comfortis which is what I give my boys. Because I hate the topical stuff, I also put on a flea/tick collar and that combination works well, for me anyway. Sorry about the miss information yesterday.