A stop-limit order is an order to buy or sell a stock that combines the features of a stop order and a limit order. Once the stop price is reached, the stop-limit order becomes a limit order to buy or to sell at a specified price.
The benefit of a stop-limit order is that the investor can control the price at which the trade will get executed. But, as with all limit orders, a stop-limit order may never get filled if the stock's price never reaches the specified limit price. This may happen especially in fast-moving markets where prices fluctuate wildly.
The use of stop limit orders is much more frequent for stocks that trade on an exchange than in the over-counter (OTC) market. In addition, your broker-dealer may not allow you to place a stop limit order on some securities or accept a stop limit order for OTC stocks. Before you enter into this type of order, you should speak to your broker or financial advisor about how the order works.