Locking magnets have several holding forces denoted in the part number. All operate from 12Vdc, with a 24Vdc option. A standard magnetic C core is set in epoxy, then mounted in the appropiate housing. Some include a monitor device that lets the access control device know when the door is closed. Brackets are available for some magnets.
Fire and safety
Other door accessories are for fire and safety provision. Break glass buttons release the door when struck, crash bars are a mechanical release, finger guards keep fingers out of hinge pinch points, door hold open magnets on fire doors, door loops for cable protection etc.
12Vdc has become the industry standard for access control and CCTV equipment. All OPERA access controls work from 12Vdc, and some have an option to use the gate automation standard of 24Vac. OPERA power supplies are 12Vdc. Regatta intercoms have their own power supplies. There are several supplies here, some including battery backup and timers.