The "Flea Killer Spot On for Pet Cat & Dog 1 ML" is likely a topical treatment designed to control fleas on cats and dogs. Spot-on flea treatments typically involve applying the product directly to the pet's skin, often between the shoulder blades or along the back, where the pet cannot lick it off. This allows the solution to spread through the coat and skin oils, effectively killing fleas and preventing further infestations. Commonly, spot-on treatments, such as those from brands like Frontline, kill fleas on contact without needing to bite the pet​

These treatments are often effective in eradicating fleas within 24-48 hours, depending on the product. It’s crucial to follow the instructions to ensure it works effectively, including not bathing your pet for a couple of days before or after treatment​Be sure to select a flea treatment appropriate for your pet's size and species to avoid any adverse effects, and consult with a veterinarian if you're unsure about the best option for your cat or dog.