Alpari (US), LLC is dually registered with the CFTC as a FCM and RFED and is a member of the NFA. NFA Member ID: 0379678.
Flags are usually preceded by a sharp advance or decline. The flag looks like a rectangle directed against the prevailing trend:

The formation of this pattern is accompanied by a decrease in volume followed by a sharp increase after the breakout. The formation takes from 5 to 15 bars. The pattern is considered to be in the middle of the trend, so after the breakout the price may move the same range as it had moved before the pattern.