ISO CR-80 smart proximity 13.56 MHz ISO14443A-4 card for secure authentication and data confidentiality: SEOS™ Unique Identifier: Ramdom UID. Allows 1 SIO (Secure Identity Object™) application in memory. Read only, does not allow writing to memory. Made of composite multi-laminated 40% Polyester / PVC. Minimum order: 100 units (in packages of 50 units).