Here's a little bit of info on martingales---they are steadily becoming more popular for many different dog breeds:
Martingale collars are also known as Greyhound Collars or Humane Choke Collars. The Martingale Collar was designed for Sighthounds (ie, Greyhounds, Whippets, Italian Greyhounds, Borzoi, Saluki, etc) because their necks are larger than their head and they can slip out of traditional side release collars; these collars have gained popularity with other breeds in the recent past because trainers prefer the humane choke aspects.
Martingale Collars have 2 loops. The smaller of the loops is called the "Control Loop". This is the portion of the collar that is attached to the leash and tightens when it is pulled. The second loop is the adjustment loop. This is the part of the dog collar that you adjust to the right size to fit your dog.
AKC Dog Show Owners prefer the Martingale Dog Collar because it does not damage the fur and will not crush the trachea. Many trainers have started to recommend Martingale Collars because they prefer its gentle choke over the choke chain. Others have learned about Martingale Collars and have made the switch just because they like them better than traditional dog collars.
Martingale/Side Release Combo collars offer the easy on/off option of a standard side release collar. This option is great especially for dogs with large heads because you can take the collar on and off without readjusting it each time to fit over the head. Please note that the side release buckle adds some bulk to this collar.
