The TropiClean Natural * Flea & Tick Repellent Collar for Cats is a full body repellant that effectively protects and defends against irritating fleas and ticks. The collar is made with natural active ingredients, cedarwood and peppermint oils, and is waterproof and breaks away under the strength of a 4.5 pound cat. The collar is available in one size that fits all cats and is effective for up to 4 months.