Collar comes in 1 size for dogs (fits up to 23" neck).

Wondercide is proven to work without the conventional ingredients. Our lineup of plant-powered sprays, spot ons, collars, and shampoos harness the power of nature to do the job. Lab-tested to protect your pet from fleas, ticks, and mosquitoes. Loved by people, pets, and pollinators. It’s all good.