The martingale collar is a dog training collar that has only a small section
on it that will tighten when pulled, thus there is a limit to how far the
martingale collar will tighten. This is different from the choke collar
which will tighten indefinitely. Proponents of the martingale training collar
say it is safer than the choke collar. Opponents of the martingale training
collar say that it is not as effective.