The PAC 21106 OPS DESFire 4K EV1 Proximity Cards are designed to provide secure access control with advanced Ops technology that reduces the risk of counterfeiting. These cards have a 4K Mifare DESFire 7 byte unique serial number that eliminates the possibility of token cloning. The card design has no batteries, making it possible for an infinite number of reads.Product Features:Comes in packs of 10CR80 card size (86mm x 54mm)Fully ISO / IEC 14443 A 1-4 compliant