A call spread is a popular options trading strategy that involves the simultaneous purchase and sale of two call options on the same underlying asset with different strike prices. The call options have the same expiration date.

The call spread strategy allows traders to limit their potential loss and profit from both bullish and neutral market conditions. The trader buys a lower strike price call option, known as the long call, and simultaneously sells a higher strike price call option, known as the short call. The premium received from selling the short call helps offset the cost of purchasing the long call.

The goal of a call spread is to profit from the difference in the premiums of the two call options. As the underlying asset's price rises, the value of the long call increases, while the value of the short call decreases. The maximum profit is achieved when the price of the underlying asset is above the strike price of the short call at expiration.

By using a call spread, traders can participate in the potential upside of an asset while limiting their risk exposure. However, it's important to note that call spreads also cap the maximum profit potential compared to owning a single call option.