i use them for my 210 pound st. bernard cause a dog i have awhile back had heart worm and died from it, so all my dogs get heartworm meds. heartworm free! they are expensive as you know what...
I got 2 pills and one crushed up used a small amount for my biocube. No red bugs.
My pack doesnt say for large dogs but it says its for dogs 50lb to 100lbs. Guess thats large.
I dont think I can sell them but would be willing to trade for something.