Hi everyone! We wanted to let you all know that in order to offer long-term product submission growth,we are migrating our product detail page URLs to a fresh format. T-shirts added on or after December 16, 2017 are already published in this format and, or beginning today,t-shirts published before this date will be migrated to the fresh format on a rolling basis over the next few months. We recommend that you Read the FAQ which we've prepared for you with additional information.
Source: amazon.com