For dogs. Fits neck to 20.5 inches. Kills fleas; ticks. Water resistant. Kills fleas for up to 3 months. Kills ticks for up to 3 months. Read entire label before each use. Use only on dogs. Do not use on cats. If you have questions or comments about this product, please write: Consumer Response, PO Box 540399, Omaha, NE 68154-0399. In case of emergency, call: 1-800-781-4738; Non-emergency, call: 1-800-224-Pets (7387).