Our Blue Mifare Classic� EV1 4K Keyfobs are RFID access control devices that are ideal for situations where traditional ID cards are not necessary. Designed with genuine NXP Phillips chips and an operating frequency of 13.56 MHz, these keyfobs are perfect for access control in a variety of settings. With a no-battery design, there are no limits to the number of reads. Product Features:Genuine NXP Phillips chipsNo-battery designSold in packs of 100 4kb of EEPROM memory Operating frequency of 13.56MHz