Our Mifare Classic� Keyfobs in black and white come with a sizeable 4Kbyte memory, and their battery-free design means they can be read an unlimited number of times. These key fobs feature authentic NXP Phillips chips and can be used with key rings, lanyards, and strap clips.Available in black and whiteGenuine NXP Phillips chipsCompatible with key rings, lanyards, and strap clips