NFC Tag Keychains - 2 NFC Keychains (Mifare 1K NDEF Formatted) - Compatible with: Android, Windows 8 Phone, WP8, AT&T Sprint Verizon Wireless - Nokia, Samsung Galaxy S3, S2, Note, LG Optimus G, HTC One Replaces Version 1 Tectiles - Lifetime Guarantee 2 Mifare Classic 1K NDEF Pre-Formatted NFC Keychain FOBs (32mm x 52mm) NFC Chip Type: MIFARE(TM) 1K classic compatible w/ NDEF Formatting already done. Compatible with Tectile. Mifare 1K Memory Size: 1024bytes (1KB), holds vCard, long text. High Quality, Long Lasting (Approx 100,000 Data Read/Write Cycles) Compatible with many Android Phones and/or NFC Readers, including the Samsung Galaxy S3, Samsung Note, LG Optimus G, HTC One Series and any other Mifare compatible NXP NFC phones. Operating Frequency: 13.56 MHz - Data Retention: Approximately 10 years. NFC allows for NO BATTERIES REQUIRED