EFFIPRO DUO SPOT-ON CATS 4PIP: properties, benefits and therapeutic uses EFFIPRO DUO SPOT-ON CATS 4PIP is a product used to protect domestic cats from parasitic infections. EFFIPRO DUO SPOT-ON CATS 4PIP is sold as a pack containing 4 pipettes for skin applications based on pyriproxyfen, a constituent with a bactericidal action that mostly weakens the nervous functions of the parasite, thus causing death. EFFIPRO DUO SPOT-ON CATS 4PIP is a product to be used