Choke collars, also known as choke chains, are a type of dog collar designed to tighten around a dog's neck when pulled. They are often used in training to correct unwanted behaviors by providing a quick, sharp correction. However, they can pose risks if not used properly, potentially causing injury or discomfort to the dog. These collars come in various materials, including metal and nylon, and are typically used for larger or stronger breeds. Many trainers recommend using alternative training collars, such as martingale collars or flat collars, which can be safer and more humane for everyday use.