From Futures Wiki

Since the dawn of commerce and trade, currency has evolved to facilitate the process by providing a medium of exchange and helping people represent a store of value. From coins to paper money, the circulating medium was developed in many cultures and the U.S. dollar is a globally recognized hard currency. The U.S. Dollar Index is a measure of the value of the U.S. dollar against six major world currencies using a weighted geometric mean. U.S. Dollar Index futures are traded on the Intercontinental Exchange (ICE) and the CME, but for this lesson, specifications will refer to the ICE contract.

Contract Size: $1,000 x Index Value

Price Quote & Tick Size: US Dollar Index points, calculated to three decimal places .010 = $10; minimum tick size is .005 = $5 per contract

Contract Months: March, June, September, December

Trading Specs: Electronic Trading Hours 8:00 pm to 6:00 pm the following day on the Intercontinental Exchange (Sun - Fri) *the trading platform is available 30 minutes before the opening for order entry. Open on Sunday night is 6:00 PM ET; Pre-Open at 5:30 PM ET