- Industry standard 125KHz RFID technology-26 bit Wiegand format-Non-contact reading for long life-Use with the Viking PRX-1, 2, 3, 5 and certain legacy 125KHz HID proximity card readers-PRX-C is a durable 0.070 thick plastic card with a slot for neck strap-PRX-C-ISO is a thin 0.032 thick flexible ISO style card-PRX-FOB is a durable key ring fob with a IP67 rating allowing it to even withstand the washing machine-Up to 253 facility codes and 65,534 card numbers available-Cannot be erased by a magnet-For Lon