Coreless keyed padlocks restrict access to property and don’t have a core. This allows them to be rekeyed or keyed into an existing system by changing out a required cylinder core. A control key fits into the padlock and actuates the interchangeable core retaining mechanism to allow the removal and replacement of the core without taking apart the padlock. They're used where padlocks and keys frequently change hands, such as in universities or hospitals, and they allow organizations to maintain security without purchasing new padlocks each time there is a personnel change. These padlocks also allow security systems to be scaled up to accommodate future needs. Standard shackle padlocks are less than 1.5" in vertical shackle clearance, while long shackle padlocks are 1.5" or more in vertical shackle clearance. Partially hidden shackle padlocks resist cutting and smashing. Breakaway shackle padlocks have a shackle that can be broken with a hammer blow in an emergency.