The Sprenger Curogan ultra plus prong collar is an excellent choice for dogs whose fur stains or discolours easily from some metals. 

Curogan is a copper-tin-alloy  with a high copper portion and some additives which make the material strong, nickel-free thus these chains  will not discolour fair haired dogs. Some dogs (less than 10%) do react to Curogan with a discoloration. Curogan is also safer for dogs with skin irritations or allergies due to it's nickel free content

Prong collars are used to give an active correction by tightening and creating a pressure that is instantly released once the dog “yields to the leash” or stops pulling. 

Please consult a professional dog trainer to receive advice on how to use responsibly

Sprenger quality made in Germany