The indicator RSI can mark overbuy and oversell in market on some degree. But when the RSI period is a big number, RSI becomes insensitive and waves near the 50-level-line.
RSI Plus can solve this problem. There are two parameters in RSI Plus. One is RSI period. The difference with RSI is that RSI period in this indicator is supposed to be bigger, which means you can use it in long term. Another parameter is Plus value. It affects the sensitivity of this indicator.
You can observe the effect by free demo. Hope you can find something big by this indicator.