【MULTIPLE UNLOCKING MODES】A) Single Mode - Unlock with one user card; B) Dual Mode - Unlock with 2 user cards together, supports up to 13 cards; C) Smartphone NFC function. 【LOW VOLTAGE PROTECTION】15,000 unlocks from 4 x AA batteries, or via USB cable. After the low voltage prompt, it can still be used approximately 100 times, replace the battery immediately. Battery not included! 【NFC Installation】1) Open the \"wallet app\" on your smartphone; 2) Click on \"keys\" or options like \"card\"; 3) Click on \"Copy your card\" or \"Blank card\"; 4) Place your card near the NFC sensor on your phone. 【HIDDEN INVISIBLE LOCK】Unlock your cabinet door without touching it! This electronic lock securely protects your personal belongings and prevents children from freely opening drawers or cabinet doors. 【ROBUST LOCK】The NFC drawer lock fits wooden cabinets with a thickness of less than 1.5 inches and can transmit through wood up to 1.2 inches thick. Perfect for drawers, cabinets, gun safes, lockers, wardrobes, and safes.