It’s important to choose the right collar for your dog. Very active dogs should wear a collar that can snap off if it gets snagged. For most dogs, a standard inch-thick fabric dog collars and leashes work well, sturdy and durable. Flea collars do help keep pests away. For training, shock/chock collars are often used. I personally object to them unless they are absolutely necessary, due to the stress they can cause the animal.