Dr Mercola Herbal Repellent Collar - Cats & Kittens Using active herbal ingredients, Dr Mercola's Herbal Repellent Collar for Cats & Kittens effectively controls fleas, ticks and mosquitoes, reducing the number of bites. Effective up to 4 months No Harsh Ingredients Repels Fleas, Ticks & Mosquitoes Fits neck up to 12" Directions for use: To be used on Cats & Kittens (4 months and older) with a maximum neck diameter of 12 inches. Remove the herbal collar from the bag and fasten it around your pet's neck. A correct fitting will enable two of your fingers to be comfortably inserted bewteen the collar and their neck. LOOSEN THE COLLAR AS YOUR CAT GROWS BIGGER. Cut off and dispose of any excess length of the collar which goes beyond the buckle, Wash hands immediately with soap and warm water after fitting. Dr Mercola's Herbal Repellent Collar is waterproof and does not need to be removed until it's time to replace the collar. For maximum protection, replace collar every 3-4 months and use simultaneously with Dr Mercola's Spot on Herbal Repellent for Cats & Kittens.