Bob Martin Flea & Tick Spot On for cats is a very effective and extremely quick treatment for the protection of flea and tick infestations for your cat. For use on cats and kittens from the age of 12 weeks old, this Spot On treatment will provide protection for up to 4 weeks with just one dosage. An easy and hassle free way to ensure your cat is protected! Available sizes:- - 4 week protection - 12 week protection - 24 week protection Price varies with size.