These hotel key cards function by running the magnetic stripe over a sensor that reads the contents of the strip and when it matches it permits access. We offer RFID Cards that work with most major lock manufacturers' RFID guestroom lock systems, including: Onity, Saflok, Kaba, Salto and MIWA, etc. Frequently used RFID chip for hotel key card: NXP MIFARE Classic® 1K (for guest) NXP MIFARE Classic® 4K (for staff) NXP MIFARE Ultralight® EV1