Preventic Two Month Tick Collar from Virbac controls infestations from paralysis ticks, indigenous ticks, bush ticks, cattle ticks and brown dog ticks in your dog for up to two months. Preventic uses a unique compound as a specific insecticide for ticks, which provides ongoing protection from the deadly paralysis tick. Preventic collar uses a slow release technology that allows the active ingredient to be slowly released from the collar over 2 months, at a consistent rate every day. Preventic prevents the attachment of paralysis ticks during this period. For effective long lasting treatment, it is recommended that Preventic collars be removed before swimming and bathing. Preventic Collars are recommended for dogs over the age of 16 weeks; please follow fitting and usage instructions on the label.