A standard Market Order executes immediately at whatever prices are currently available in the order book, forcing your trade to eat through deeper, worse price layers if volume is thin. A Stop-Loss Limit (SL-L) order protects you by setting a mandatory price cap, so your trade will only fill at your specified limit price or better, eliminating unexpected impact cost spikes. Note: Indian exchanges have discontinued SL-M orders in the options segment to protect traders from these exact execution traps.