A rope collar with a sliding stop, so it tightens to a preset limit and no further. The stop is the part that matters and it should be set before the collar ever goes on the dog.
Braided rope with a metal ring and adjustable stopper, fifteen size and colour combinations.
Setting the stop correctly
Fit the collar over the dog's head, then slide the stopper so that at its tightest the collar still sits comfortably with two fingers underneath. Set properly, it cannot close beyond that point. Set carelessly, it is a choke collar, which is a different tool with different risks and is not how this is intended to be used.
What it is good for
Quick on and off, which makes it useful at a training class, a groomer, or moving a dog between a car and a building. Rope sits high on the neck and gives clear directional feedback for a dog who already walks politely.
What it is not for
Not for a dog who pulls, not for unsupervised wear, and not for tie-outs. Use a harness for pulling. If you are in Quebec, note that provincial regulations restrict the use of choke and similar collars on animals.