William %R Scalper or WPR Scalper tool is used with small time frame : 5 , 3 or 1 minute, it uses two different William %R indicators : one for fast move with 9 period WPR9 and one slow with 54 period WPR54. You can find buy zone when WPR9 < -90 and WPR54 < -80 and sell zone when WPR9 > -10 AND WPR54 > -20. For experience user only you can adapt the two periods and threshold levels to your need. You can use only WPR9 to place trade and validate trend with WPR54.