Lockboxes are what Realtors use to have house keys safely available to be used in showings of homes they put on the market. There are two types of lockboxes, combination and electronic.
Electronic lockboxes can only be opened with electronic keys; the display on the key will tell you to press the bottom of the container to open it after you have entered the correct code. When you press it, spring action pushes the chamber back down and the key to the house rests in the chamber.
With a combination lockbox, you enter the combination and press a manual-release button and the front will open up. The key will be inside.
You need to be a member of the National Association of Realtors to possess an electronic key. Every key has a personal code tied to the Realtor, so every time a house is shown it transmits a report that says what time it was shown and who showed it.
Combination lockboxes are safer than a key being in an office, since a key can be misplaced and lost easily. They require a manually entered code only available at the listing office.
When a lockbox releases its shackle, the top pops up just like a padlock. To release the shackle on an electronic lockbox, you must use your electronic key and enter your personal code and also a special code that is assigned to each individual lockbox.
To release a combination lockbox, you must enter the combination to open it, and there will be a manual-release trigger on the inside.