The ES-1 Is a door controller designed to operate a door strike or magnetic lock upon receiving a valid card read and or keyless entry code from Wiegand devices.One ES-1, One or two Wiegand devices and door strike or magnetic lock of your choice is required for each entry point. The wiegand device used may be the viking model HD-1 Proximity Card reader and or the Viking model HID-2 Wiegand output Keypad or any other card reader, RF transmitter or digital keypad that outputs the 26 but Wiegand format. Up to 250 valid Wiegand codes can be programmed into the ES-1.