Iverhart Max for Dogs 12-25 lbs, Blue, 6 Pack (1016142)
The ivermectin in Iverhart Max for Dogs 12-25 lbs, 6 Month (Blue) is a broad-spectrum antiparasitic that kills heartworm larvae in the tissue stage. Iverhart pet meds prevent potentially deadly heartworm disease and control worms.
Iverhart Max heartworm protection
Seems to work great, I have not had any problems with it.