A dog pin brush is a type of grooming tool used to brush and detangle a dog's fur. It typically has long, flexible metal pins with rounded tips that are set into a rubber or plastic base. The pins are designed to penetrate deeply into the dog's coat without scratching or damaging their skin, and can help to remove loose hair, dirt, and tangles. The brush can be used on most types of dog hair, but is particularly useful for dogs with long or curly hair that is prone to tangling. Regular brushing with a pin brush can help keep a dog's coat looking healthy and shiny, and can also help to prevent matting and other grooming issues.