Seresto for Small Dogs 8 Month Flea and Tick Prevention CollarSeresto Flea and Tick Collar for Small Dogs up to 18 pounds provides continuous 8 month flea and tick protection. Unlike oral flea and tick prevention products that require a bite the Seresto collar repels fleas and ticks and kills through contact; no biting required. Seresto dog flea collars are made with a long lasting 8 month formula for continuous release coverage over your dog? s skin and coat. Vet recommended Seresto collars are water resistant