Hartz 3 in 1 flea and tick collar doesn't work at all. It does nothing at all to repel or kill fleas and ticks. I live in an area where fleas and ticks are very heavy and they are becoming harder and harder to control and get rid of from pets and homes. I tried the collars before flea season kicked in this year and the collars didn't stop our animals from becoming flea infested. I have been trying to find products that will protect our cats and dogs from fleas, but won't cost me a fortune. We have 3 dogs and 6 cats and the flea problems can get very expensive. I figured the hartz collars wouldn't work because of fact that most every hartz product I've tried hasn't held up to claims. Hertz products are easy to find in most grocery stores and shopping centers. They are much cheaper then the other brands but unfortunately with flea control it seems that you get what you pay for. I have noticed any of the topical flea products that work cost a fortune and they are hard to get without visiting a vetrinarian. I suggest skipping the collars all together and going for the topical flea prevention. They are costly especially if you have multiple pets but in the end it's worth it to avoid becoming infested with fleas. The best thing to do is make sure it doesn't become a problem or its very hard to get rid of them and also expensive. Fleas are tough little buggars and they do put up quite a fight when it comes to getting rid of them. I hate to spend money where I don't have to, but with fleas I've been shown time and again that the cheaper the product the less effective it is. I hope eventually a company will come out with a line of flea products that will work great with a low price but until then I will have to spend more money. Hartz products are super affordable even with multiple pets, but rarely do the products work. They make lots of flea and tick stuff but as someone who's tried them take my word for it and skip them even though they are so cheap! It's not worth it.