Make sure you measure correctly. I used the old belt as a guide to measure the size I needed. It doesn't have to match the waist of your pants. I have never heard of Nickle Zero or Nickel allergies but I am impressed with the quality of this product. This belt is made of very high quality leather. It was a bit stiff at first but as I used it more it loosened up. The skin is very soft and pleasant to the touch. The clasp is strong and easy to use. It's like the expensive belts you find in expensive department stores.