2016 -S Sealed United States Mint Monster Box of American Silver Eagles - 30th Anniversary. A 2016 Monster Box of American Silver Eagles with a 6 digit serial number starting with the number 4 is a box minted at the San Francisco Mint as stated in the Freedom of Information Act. These specific boxes also came with a wide strap. West Point Mint couldn't keep up with demand that year so San Francisco supplemented the mintage with these boxes. There is no mint mark on the rounds, so if grading, it is important to send in the Sealed box to NGC or PCGS.
You can also confirm this with PCGS and there bulk department. Not many of these boxes were left sealed or sent in for grading... Making these a rare opportunity. The item "2016 S Silver Eagle Monster Box 500 oz ASE 30th Anniversary San Francisco Mint" is in sale since Sunday, October 21, 2018. This item is in the category "Coins & Paper Money\Bullion\Silver\Coins".
The seller is "qwest4" and is located in Olmsted Falls, Ohio. This item can be shipped to United States. Mint