If you buy a stock at 100 rs. your generally wants your stop loss limited to 1 rs (if it comes to 99 you want it to sell automatically). suppose it went up to 105 then what?? do you will want to sell it at 99. No. in this scenarios you can use 'trailing stop loss'. you can set it to 1 rupee so if the price starts falling, the system will automatically sell it at 104rs. watch the video below.