HID Wiegand SensorCards use the proprietary Wiegand technology of HID, which is practically impossible to counterfeit. HID Wiegand SensorCards can't be copied or altered and are immune to RF interference and external magnetic fields. The way the Wiegand technology works is that it is an embedded code strip that has trillions of possible codes which are laminated under pressure, which creates the solid vinyl card. If anyone tries to get to the code, it will destroy the HID Wiegand SensorCard.