The Martingale collar is designed tohelps prevent a dog from slipping out of their collar. This is why the collars are recommended for dogs where the head is slimmer than the neck e.g. greyhound. Unlike traditional collars that have to be buckled uncomfortably tight to prevent escape, these collars are comfortable around the neck until engaged. Adjusted properly, they contract snugly to prevent escape when needed
A Martingale Collar sold by Pillie Pooches is not intended to be used for training. It is intended to keep dogs safe where a standard collar is not suitable as it would slip over their heads.