A single active ingredient can kill the fleas already on a dog, but it does nothing about the eggs and larvae already sitting in the carpet, which is why the more useful spot-on treatments carry two ingredients doing two different jobs.

This is a spot-on solution for small dogs only; each pipette contains 67mg Fipronil and 60.3mg (S)-Methoprene. It's applied as a spot-on: half the pipette at the back of the dog's neck, and half between the shoulders, for dogs weighing 2-10kg and over 8 weeks old.

• Spot-on solution; each pipette contains 67mg Fipronil and 60.3mg (S)-Methoprene
• Kills fleas within 24 hours, preventing reinfestation for up to 8 weeks
• Kills ticks within 48 hours, protection lasting up to 4 weeks
• Prevents flea eggs and larvae developing for up to 8 weeks; also treats biting lice
• For small dogs only, 2-10kg and over 8 weeks old
• Applied as a spot-on: half the pipette at the back of the neck, half between the shoulders

On age, weight and water. This is for small dogs only, 2-10kg and over 8 weeks old - it isn't formulated for dogs outside that band. Bob Martin's own caution also asks you to keep treated dogs out of water for 48 hours afterwards, since both active ingredients are harmful to aquatic life, and to avoid letting a freshly treated dog sleep against anyone, especially a child.

Who it's for: owners of a small dog, 2-10kg and over 8 weeks old, who want one spot-on covering fleas, ticks and lice rather than three separate products.