In the event the crossbow is fired without an arrow, the Guardian™ Anti-Dry-Fire System, a self-contained unit housed inside the mount, catches the string preventing the crossbow from dry firing, thereby preventing possible damage. It also features a built-in release allowing for easy de-cocking of the crossbow without having to fire an arrow. The Guardian system is standard on some Excalibur Matrix models, and is available as an upgrade part for all other Excalibur crossbow models.