A stop order is an order that becomes a market order when the futures contract reaches a particular price level. A sell stop is placed below the market, a buy stop is placed above the market. Stop loss orders are most often used by traders to limit losses; however, stop orders can also be used to enter a futures market (typically on a break-out). The important thing to keep in mind is that stop loss orders are only filled if the market moves unfavorably; buy stops are filled if the market goes up to the stated price and sell stop orders are filled if the market drops to the stated price.