This video will illustrate the Double Top & Double Bottom Reversal Chart Patterns with real chart examples and listing specific characteristics for each one regarding the formation of the pattern itself , the % of Retracement and volume rules for trading these Chart Patterns .. 

Note : the time of forming these patterns is related to your trading style..  another words Double Top & Double Bottom Patterns can occur on any time frame so the time needed to form the pattern is directly proportional to your trading time frame .. 

see also .. 

Where to look for Price patterns ?