Plant-based repellent and preventive - no pesticide. The alzoo™ flea & tick collar utilizes plant-based active ingredients to effectively repels fleas, ticks and mosquitoes and help prevent bite and pest irritation. Sustainable, safe & powerful. Proven, safe and effective for dogs and kids when used as directed. Laboratory tested. Cruelty free, made in the usa using recycled and recyclable packaging. Durable & suitably sized. Effective for up to 4 months on fleas & ticks. Replace collar every 4 months for maximum protection. For medium-sized dogs: 16-40 lbs. Waterproof. The alzoo™ flea & tick collar is waterproof and does not need to be removed when bathing your pet. Combinable. If your dog currently has fleas, use with alzoo™ f&t spray. In high infestation area use with alzoo™ g+ environment powder, alzoo™ f&t home spray and/or alzoo™ f&t yard spray. Variety of skus in the f&t line to please users who prefer one type of product or another.