Beaphar Soft Cat Flea Collars contain a powerful insecticide that kills fleas on your cat and prevents them from re-occurring for up to 4 months. Effective, comfortable and fashionable, they feature a silver bell so you can hear when your feline friend is nearby! These velvet collars can be adjusted to fit any cat. Suitable for cats and kittens over 12 weeks of age. Measures 30cm. Active Ingredient: Each collar contains 456 mg (18% w/w) Permethrin (cis:trans 40:60) .