These are EM standard cards compatible with access control systems and electronic locks, such as those used by Rockman Japan and Lavish. The leftmost card is a waterproof type, 20 cards in total, credit/cash card size, 1.0mm thick. The second from the left is a waterproof type, 20 cards in total, credit/cash card size, 0.8mm thick. The rightmost and second from the right are clamshell types, 40 cards in total, credit/cash card size, 1.8mm thick. All cards have a card number (UID) printed on them. Operation has been confirmed with dedicated reading devices. Since they are intended for security purposes, they will be shipped anonymously. Built-in chip: EM4200 Frequency: 125Khz *If you are unsure of compatibility with your device, please provide the model number and we will investigate. Please feel free to ask any questions.