Activyl for Dogs & Puppies is a monthly spot-on flea treatment that works like no other flea product on the market. Activyl works by using a method called bioactivation, a method in which the active ingredient, indoxacarb is fully activated by using the flea’s own enzymes. It kills not only adult fleas, but also flea eggs and larvae too, thereby, breaking the flea’s lifecycle and preventing re-infestation. It is available in 6 month supplies depending on your dogs weight.?