Give your pooch superior pest prevention with the Zodiac Flea & Tick Collar for Large Dogs. This collar works from head to tail to ensure he’s covered from every angle, and the active ingredients work fast to kill and repel adult fleas and ticks—including those that may carry Lyme design. It starts working on contact to give your pet fast relief, and it amazingly continues to work for 7 months of formidable pest protection! Plus, it’s water-resistant, which means it keeps on working even after multiple baths or a swim in the lake or pool.