Keyed padlocks and padlock keys are detachable locks that open with a key. They’re used across many applications to prevent unauthorized use, theft, or vandalism. Keyed padlocks are more secure than combination padlocks because they don't have a dial that can be cracked with trial and error, and their overall construction prevents shimming. Keyed alike padlocks allow authorized users to open all padlocks in a set with the same key. Keyed different padlocks can only be accessed by one unique key. Master keyed padlocks can only be accessed by one unique key or a master key. Each padlock in the master system has its own key, which cannot be used on other padlocks, but a master key can open each lock in the set. Coreless keyed padlocks don’t have a core, allowing them to be rekeyed or keyed into an existing system by changing out a required cylinder core. Master keys open master keyed padlocks.