Revolution for Dogs 21-40 lbs (10.1-20 kgs) is a effective flea & heartworm control treatment. This Revolution for Dogs 21-40 lbs (10.1-20 kgs) comes in a 12 pack, which will treat fleas & heartworm on one medium dog for 12 months. Revolution for medium Dogs comes in a red packet. Revolution for very medium Dogs kills adult fleas, kills flea eggs, kills flea larvae, treats heartworms, treats ear mites and treats sarcoptic mites. Revolution red flea & heartworm treatment is a very easy way to control and get rid of fleas, heartworm, worms and ear mites for your dog. To buy Revolution for Dogs 21-40 lbs (10.1-20 kgs) flea & heartworm control in a 12 pack, just click add to cart and you’re on your way to making your dog flea & heartworm free.