An option strategy that achieves its maximum potential if the underlying security rises far enough, and has its maximum risk if the security falls far enough. An option with a lower striking price is bought and one with a higher striking price is sold, both generally having the same expiration date. Either puts or calls may be used for the strategy. This is one of a variety of strategies involving two or more options (or options combined with an underlying stock position) that may potentially profit from a rise in the price of the underlying stock.