Bob Martin Flea Clear Spot On Solution 3 x 50mg for Cats Over 1kg is for killing fleas on your cat. It is applied at the back of the cats neck and between the shoulders. Each Bob Martin Flea Clear treatment provides protection against fleas for up to 5 weeks. Bob Martin Flea Clear Spot On can be used on cats over 2 months old and is suitable for use in homes with both cats and dogs. Bob Martin Flea Clear Spot On can be used on cats over 2 months old and is suitable for use in homes with both cats and dogs. Regular treatment of all cats and dogs in the home with effective flea killing products together with regular vacuuming of your pets bedding and resting areas is needed to protect your pet and home from fleas. Do Not Use On Rabbits.