Contains 9.7% Fipronil to kill fleas, ticks and chewing lice. Fipronil collects in the oils of the skin and hair follicles, and continues to be released from hair follicles onto the skin and coat, resulting in long-lasting activity. For dogs 8 weeks and older.
I've tried several products that use Fipronil and other than the big name brand (costing almost twice as much) this is the only one that really works for ticks. It's long lasting and I couldn't be happier with the results.