Plastic parts holding the adjustment rack broke after 10 years. Looked at the part number and ordered over the internet. Parts arrived quickly and everything fit, except the diameter of the wheels was too big to fit into the rail. This time I called and spoke with customer service. They had me give them the serial and model numbers. Upon locating those numbers customer service determined that there were two parts that could be ordered, both identical with the exception of the size of the wheels. APP credited my first purchase and sent the new set the next day just in time for Christmas and the family food situation. Prompt and wonderful service!