What a martingale does
A martingale has a second, smaller loop. When your dog backs up, that loop closes a little and the band becomes just too small to slip over the head. Once the dog walks on, the band falls back to its open position.
The difference with a choke chain is that a martingale does not keep tightening: the loop has a limit. Useful for dogs whose head is narrower than their neck, such as sighthounds and many spaniels.





