Frontline Plus for Dogs Extra Large Dog (89 to 132 pounds) Flea and Tick Treatment, 6 Doses Amazon 42.96 $42.96

https://www.amazon.com/gp/aw/d/B0…ref=plSrch
Frontline plus 6 dose for large (89 to 132 pound) dogs. If you have a smaller dog you can split the dose and be set for a long time.
Shipping is slow on this one but it is sold and shipped via amazon so should be knock off safe.