Examples:

• Our superior technology is our ace in the hole.
• As a strategy, it's better than an ace in the hole.
• His embarrassing secret is my ace in the hole, and I plan to reveal it to everyone the next time he mocks me publicly.
• His strength in a crisis is an ace in the hole.
• George seems awfully confident. He must have an ace in the hole.
• She's keeping all the details of their unscrupulous business practices as an ace in the hole should they ever try to fire her.
• An ace in the hole is any argument, plan or thing kept hidden until needed. It is used especially when it can turn failure into success.
• As a strategy, it’s better than an ace in the hole.
• When Tom bet all his money in the game he did not know that the gambler had an ace in the hole and would win it from him.
• Your competitors do not know that you are an ace in the hole.