The Advantage II also goes between the shoulder blades. I've been using it for a few years now. My four are strictly indoor cats but I still treat them during the Summer months, because, guess what? They got fleas last year and then from the fleas they got worms! I was so mad. I had no idea they could get either since they don't go outside. We did have that mouse problem, though, and I think I read that mice carry fleas and fleas can transmit worms. So I continue to treat them. I like the Advantage because it works really well on fleas.