A stop-limit order is a type of trading order that combines the features of a stop-loss order with those of a limit order. It is designed to help traders reduce their risk by setting parameters that help protect them from large losses. Unlike regular limit orders, stop-limit orders will only be triggered when a stock's price reaches a certain level, referred to as the stop price, and will only be executed if it trades within the predefined limit price.

The main purpose of a stop-limit order is to help safeguard traders from large losses. For example, say a trader buys a stock at $50 and wants to protect his or her position from a large price decline. The trader could set a stop price at $45, and set the limit price at $43. Once the stock falls to $45, the order will become a limit order to sell the stock at $43 or better.

Stop-limit orders are especially useful for reducing risks associated with volatile markets. If a trader is expecting a big price movement and doesn’t want to wait around to manually adjust the order, they can set up a stop-limit order in advance and be sure that they won’t lose more than they planned.

Traders can also use stop-limit orders to lock in profits. When a stock is rising, a trader can set a stop-limit order with a higher limit price than the current market price. If the stock continues to rise, the order will be triggered, resulting in a profit.

It is important to note, however, that a stop-limit order is not guaranteed to fill. This is because the price of the stock might not trade within the limit price. If the limit price is set too tight relative to the current price and there is no liquidity in the market when the order is triggered, it might not fill.

In conclusion, stop-limit orders can be a powerful risk management tool for traders. By combining the features of a stop-loss order with that of a limit order, traders can have precise control over when the order should be triggered and receive a guaranteed price. However, it is important to understand that there is no guarantee that a stop-limit order will fill as price movements can be unpredictable.