A currency board issues notes and coins backed 100 percent by some foreign currency. The board guarantees full convertibility between its currency and the foreign currency it uses as its reserves. Unlike central banks, currency boards cannot act as lenders of last resort nor can they create inflation, although they can import the inflation of the currency they hold in reserve. Typically, this is well below the level of inflation which caused countries to resort to a currency board in the first place. For one thing, they have been taught by at least two generations of economists that the gold standard is impractical.
Gold is too costly.
Those who allude to the high cost of gold have in mind the resource costs of mining it. They are certainly correct in saying that more resources are expended to produce a dollar's worth of gold than to produce a fiat dollar. The cost of the former at the margin is very close to a dollar, while the cost of the latter is under a cent. The flaw in this argument is that the concept of cost they employ is too narrow. The correct concept economically speaking is that of opportunity cost, defined as the value of one's best sacrificed alternative.