“Absolutely no complaints about this product. It is used year round since our western NC location sometimes has mosquitos into late Fall. Our dogs are beloved Therapy Dogs so we want to afford them the safest and best protection. We have adopted ex-racer greyhounds....they can be sensitive to certain medications and anesthesia. When the rescue recommended heartworm preventative 'Interceptor' became unavailable, I did thorough research and replaced it with first Heartguard Plus (also once hard to order) and now this product.....seemingly a generic substitute. Because of its much lower cost and same effectiveness, I will continue to use and recommend it to others.”