Maybe you’ve locked yourself out of your car, keys nowhere to be seen, lost in the ocean for all you know. Whether you wait to get in with your dealership to replace it, or contact an automotive locksmith professional to save the day right then and there, it’s good to know the basics of the magical invention we call a key fob.

A fob is a small electronic security device with built-in authentication protocols and/or mechanisms. These allow whoever possesses it to enter a secured network or location in order to access data or services. A key fob is designed to be small so that it can be carried around inconspicuously just like a key chain.  When we’re talking about a regular fob, it’s typically a separate device, often rectangular, flat, and non-descript. These can allow you to get into work, the gym or through other doors that are electronically locked. When it comes to car key fobs, they tend to be integrated into the key, usually wrapped around the head of it, so you can lock, unlock, start your car, or sound its alarm, all at the push of a button. You may have heard the term “remote keyless entry” or RKS instead.

Key fobs operate like remotes, and are wirelessly programmed specifically to your vehicle, so you can’t access other people’s cars and vis-versa. Whether it’s a brand new or replacement key fob, someone has to program the fob. It’s a fairly simple process, if you know what you’re doing, but if you’ve already purchased a replacement fob, you may want to let the professionals program it for you at the same time.

Sometimes, the buttons on the key fob themselves will stop working. This might be due to a dead fob battery, which is cheap and easy to replace yourself. If replacing the battery doesn’t do the job, your key fob may need new electronics altogether. Ordering them and replacing them DIY is much less expensive, but then comes the hassle of learning to program it yourself too.

If you lose or break the entire key fob, then you’re looking at a complete replacement. The cost of replacing a key fob can vary quite a lot, depending on who’s doing it and what it’s for. Dealerships, including the programming, can go from $200 to $500 depending on the model of car. Typically, automotive locksmiths are less expensive and much quicker to access.

Key fobs can work like magic, if we don’t lose them. Nowadays, dealerships, auto shops, and locksmiths can all repair or replace the key fob for you. You can also order many parts online, or purchase them in store, if you feel like trying your hand at DIY. But because they’re programmed like remotes, you’ll need to read up a bit. You may find that if you’re in a situation that you need to replace a key fob altogether, you’ll probably want to just purchase it and let the professionals handle the programming too.