FIPROtec Combo spot-on solution for dogs contains Fipronil & the insect growth regulator S-methoprene. These ingredients not only kill adult fleas, ticks & biting lice but also impedes on the flea life cycle. This results in the prevention of any exposed eggs and/or larvae from developing in your home for up to 8 weeks. Key Features & Benefits Kills adult fleas for up to 8 weeks. Kills ticks for up to 4 weeks. Effective against fleas, ticks & biting lice. Prevents eggs laid by exposed fleas from developing for up to 8 weeks. Which Treatment Will I Needspot On for Small Dogs: Suitable for dogs over 8 weeks of age & weighing 2-10kg Spot On for Medium Dogs: Suitable for dogs over 8 weeks of age & weighing 10-20kg Spot On for Large Dogs: Suitable for dogs over 8 weeks of age & weighing 20-40kg How to Apply 1. Hold the pipette in an upright position, twist & pull the cap off.2. Turn the cap around & place the other end of the cap back on the pipette.3. Push & twist the cap to break the seal, then remove the cap from the pipette.4. Part the coat on the back of the animal at the base of the neck in front of the shoulder blades until the skin is visible.5. Place the tip of the pipette onto the skin & squeeze the pipette several times to empty its contents completely & directly onto the skin in one spot.