Unlike the regular 2017 clad proof set, this special set features seven 90% silver issues. Included with that precious silver content are the years America the Beautiful commemorative quarters, as well as a silver Roosevelt dime and Kennedy half dollar. The set also contains a Lincoln cent, Jefferson nickel and Sequoyah Native American dollar. This official U.S. Mint set is not only desirable due to the precious silver content, but also for its expected limited mintage. Silver proof set outputs are always far below the regular proof sets production numbers.