The classic key chain is particularly robust, break-proof and waterproof.|The cover part is ultrasonically welded. It is not possible to open the housing tag.|In the RFID technology MIFARE® DESFire®, the key chain is available in the so-called speed version. With this version, the reading distance is greater than with a normal MIFARE® DESFire® key chain.|The serial number is printed on the key chain.