This is the spike indicator , determining the highest high and lowest lows of price in the given period , 

it is also a zigzag indicator , to it may recalculate the values  or repaint if a new higher high or lower low forms in that given period,so beware

How ever the indicator can be very powerful when used with other technical indicators for entry comfirmation 

Be sure to check out some of my other premium products which are more accurate and reliable