Dog training professional prong collar/pinch collar.

At first sight prong collars (or pinch collars) may seem to be cruel equipment but in fact these collars are more comfortable for dogs than for example choke chains. Prongs resemble the teeth of dog's mother. Using prong collar owner can easily convey necessary messages or signals to the dog.
  This collar is made in Germany by well-known Herm Sprenger company. Special production techniques, the highest quality materials and craftsmanship make Herm Sprenger products superior. You can purchase original and top-quality choke chain collars in ForDogTrainres Japan on-line shop.
  It is also non-allergic.

Other important features of this dog collar are that it prevents tearing your dog's fur out and don't cause tension on your dog's neck.
  Moreover, this collar has quick release snap hook (on loop chain) that allows to take off collar very quickly and easily.

Using this prong collar (pinch collar) you can train your dog, correct dog's behavoiur or teach your dog some obedience commands or leash manners. It's  also a great product for agressive dogs.
 
Note:
Remember, that prong dog collars are safe if used properly! Prong collars are classified as professional equipment for dog training so before using this type of collars, it is necessary to consult with professional dog trainer.
It's not recommended to use prong collars for puppies (under 6 months).
Never put on or take off pinch/prong collar by slipping it over the dog's head!
Correct fit is significant for safe and easy use of this collar type.
Please, measure your dog properly as shown below before purchasing this product!

How to size your dog for the pinch/prong collar
Prong collars are put on and taken off by hooking/unhooking links that allows to snap/unsnap the collar.
Please, measure, the neck circumference of your dog (see the blue line on the picture). After that add approximately 5 cm to the length you've already measured.