If you have a key fob and have ever been curious about the circle arrow button and its function, here's what it means.

There’s usually a mechanical key hiding inside the key fob for cars with push-button start systems, so you can still unlock your door if the car battery or your fob battery runs out of juice.

With push-button start systems, you can start your car effortlessly. As long as the key fob is inside the vehicle, a simple press of the button is all it takes.

If you're in a pinch and need a new copy of your car key, Ace Hardware may be the better alternative over the dealership, but it depends on what car you own.

There’s usually a mechanical key hiding inside the key fob for cars with push-button start systems, so you can still unlock your door if the car battery or your fob battery runs out of juice.

New key fobs must be programmed with codes that the vehicle has to read before it unlocks the door or allows starting the engine.

Some automakers have even expanded the remote start button's functionality and/or use a different icon — that's why BMW has a diamond button on its key fob, for instance.