The TDSi 2920-3004 1K Mifare Sector 4 encoded cards are designed with passive technology, which eliminates the need for a battery. This allows for an unlimited number of reads, making it an efficient and reliable option for your security needs. Each card comes with a unique printed serial number, which enhances the security and simplifies the issuance process.Available in packs of 100CR80 card size (86mm x 54mm)Operates at 13.56 MHz frequency