In 2011, Mike Caldwell created the Casascius physical Bitcoin collection. Since then, this series of Bitcoin collections has become extremely precious. However, on November 27, 2013, Caldwell had to suspend the sale of all his products containing digital Bitcoin. Throughout the manufacturing of Casascius, the coins and bars minted by Caldwell contained 1, 10, 25, 100 and 1000 BTC increments. In the past two months, a group of people redeemed their Casascius collection, and on December 23, someone redeemed the Casascius collection with a specification of 100 BTC (worth $ 723,000).