A complex option trading strategy (a box) that combines a lower-strike long synthetic futures and a higher-strike short synthetic futures. The long and short positions cancel out each other, and the net position is a net debit. Actually, this strategy is four-legged; it stands on two longs and two shorts. Essentially, it is based on buying and selling equivalent spreads, and as long as its cost is significantly below the overall expiration value of the two spreads (the bear put spread and the bull call spread), the long box allows an investor to lock in a risk-free profit.