You are buying twenty (20) NEW fasteners. They are door panel nail retainer trim pad clips inserts for 1961 1962 1963 1964 1965 1966 1967 Chevrolet  Belair , Biscayne and Impala 2 door models . These are made of nylon and are oblong / oval shaped. They will fits 1960 - 64 Chevy Corvair 2 door model cars. These clips push into a oblong / oval hole in your door and take a steel nail door panel clip that is on the back of the door panel.
These may fit other GM models not listed.
Please note the door panel nails clips are NOT included in this auction. 

Please compare your old clips to the photos as there are other door panel clip that look similar. WE do carry both style clips.