A straddle is an options trading strategy that consists of buying a put option and a call option with the same strike price, expiration date, and underlying security. It is the simultaneous purchase of a call and a put option of the same stock at the same strike price and expiration date. Thus, the same total investment is required. A straddle is specifically designed to benefit from price movements in either direction, hence making it a popular strategy in the volatile securities market.

The main advantage of a straddle is that it is designed to make profit even when the stock doesn't move in either direction. If the price of the underlying security stays between the strike price of the call and the strike price of the put, the investor will not incur any losses. In this case, the investor will be able to keep the premiums paid for both the call and the put.

However, the main challenge associated with a straddle is that it requires a significant amount of investment to make a profit. In order to benefit from gains on both the call and the put, the investor must buy an option for each security being traded. This means that the investor needs to pay for the premiums for both the call and the put, which can easily erase any potential profits.

As such, a straddle should be used only in the case of heavily volatile investments, such as the ones in the stock market, where there is a greater potential of movements in either direction. Also, in such cases, the profits need to be greater than the total premium paid in order to make a profit.

Overall, a straddle is an options trading strategy that consists of buying a call and a put option with the same strike price, expiration date, and underlying security. It is a risky but profitable method more suitable for volatile investments, where a large price movement is more likely. When used correctly, the straddle can be a great tool for generating profits for investors.