TropiClean Natural* Flea & Tick Dog Repellent Collar for Large Dogs is used to protect and defend against irritating fleas and ticks. This water-proof collar acts as a full-body pest repellent solution that effectively protects your furry friend. Use with other Natural* Flea & Tick products such as Yard Spray and Max Strength Shampoo for additional pest protection. *Made with natural active ingredients.• **Powerful Pest Deterrent** — Collars provide full-body protection against irritating fleas and ticks.• **Long-Lasting Pest Control** — When used as directed, the collar's natural* yet powerful ingredients help to effectively repel fleas and ticks for up to four months.• **Perfect Fit for Large Dogs** — Adjustable collar offers a flexible fit for large dog breeds with neck sizes up to 25".• **Water-Proof Solution** — Dogs are free to splash and play! Collar's repellent effects will not wash away in, or around, water.• **Cleaner Solution** — Natural active ingredients offer a healthier alternative to synthetic products made with pyrethrins or permethrins.