This is a simple options strategy and involves simultaneous buying of at the money put and call option with same strikes and same expiry. Long straddle is used when the the price of the underlying asset is expected to break a price range or when there is expected increased in volatility (e.g. major economic data release or central bank decision). Potential profit is unlimited, while the maximum loss is limited to the sum of the premiums paid.
P&L at expiry