These contact points were specifically designed for use on dogs with smooth, short or hairless coats. Working with the X Series of collars 640X, 280X & 1900X.
We find that dogs such as the Doberman, Pointers, French Bulldogs etc sometimes react to the nickel in standard contact points.
One of our own dogs has one of these on her collar, not becuase she has an allergy, but just because it is nicer and more comfortable for her to wear.