The double tops formation are trend revesal pattern occurring after a strong bullish trend; the market is going to push the market with strong buy orders which will reach a market price that can't be crossed; it will bounce back to test a neckline then, move up again to test the second top! The second top is therefore characterized by the fact that it will test the previous top but won't be able to close or break at previous price ( a little bit below the previous top), giving us a signal of a coming downtrend.
The Double bottom formation is also a reversal Trend, Which occurs after an extended downtrend; thus, we can observe the formation of a two valley's shapes, pointing bottoms down levels. While they are identified, we need to take some actions