There are different sizes of pinch collars; for large dogs, for small dogs, miniature pinch for toy sized dogs. The reason it is called a pinch collar is because you have to pinch on the links to put the collar on and remove it from the dog.
Sometimes these are called prong collars, but that I think is the wrong word. Because the prongs on the collar, when used correctly, mimic the teeth of a mother dog in correcting her litter. Watch the mom and you know how to use the collar.
The dog harness, instead of a collar, has become popular because advocates say it works the same as a horse harness, but I say this is flawed thinking. Because with a horse you need a harness because you ride it. You don’t ride on a dog. When on a horse you are close to it’s head when you pull on the reins, no so much with a dog.
A dog collar is used for identification of a dog, not for walking or training. You can also attach a pinch collar to the dog collar as a back up in case the pinch comes loose (which only happened once to me, and it was my fault). A dog collar has some give to it, which makes it hard to lead or control the dog.
With a pinch collar, you don’t need to pull on it to use it correctly. Let the dog pull on it and make the corrections. You use hand and voice commands to lead the dog to listen and have eye contact with you. The pinch collar provides a night and day difference in the response from the dog.
This and more reasons is why I always use a pinch collar. Do an internet search on how to properly use it, and don’t listen to anyone who doesn’t use it.
The Thoughts Behind My Thinking 