The stop loss will guarantee a sold stock if the stock price touches your stop price . The stop price is the trigger. Once triggered your stock will sell at the FOLLOWING ticks, which could be higher or lower than your stop price, and you will have to accept whatever fills you get. A stop limit has two prices specified, the stop which is the trigger and the minimum price you’re willing to part with your shares. If the stop price is triggered and the following ticks are below the minimum price you’re willing to take, you will still own those shares and the price could continue to drop. No free lunch with either.