Features 504 Bytes Memory: This Nfc Card Adopts Ntag215 Chip, Has 504 Bytes Memory, Providing Sufficient Storage Space to Quickly Write The Desired Information. Lock Function: The Nfc Card Has Read Write Lock Function, Which Can Be Repeatedly Edited Or Read Only. Cannot Edit Or Reset After Setting to Read Only. Waterproof: The Ntag215 Card Is Made of Waterproof Pvc Material And Can Be Placed Outdoors Or Near Water Without Losing Its Function. High Stability: The Surface Is Smoothly And Glossy, Hard Wearing, Stable, Odorless, And Safe. Please Rest Assured to Purchase! Wide Application: The Set Contains 30 Pcs Nfc Cards, Which Are Compatible with All for Android Phones And Other Devices Specification: Item Type: NFC Card Material: PVC Size: Approx. 22x30mm/0.87x1.18in Operating Frequency: 13.56MHz Available Memory: 504 Bytes Function: Read, Write, Rewrite, Read Only Package List: 30 x NFC Card Note: Not supported to use on metal surfaces. Package List 30 x NFC Card