1. a close outside of the 2.0 Bollinger Band (20 day, SMA
2. a close back inside the 2.0 Bollinger Band - this issues the signal
3. a higher close (sell) or lower close (buy) than the close of the day back inside the 2.0 Bollinger Band - this confirms the signal.
Once you get those 3 things a major reversal usually occurs within the next week. The sell signals are far more accurate than the buy signals.