Panel material: zinc alloy Password length: 4-7 digits Lock body material: steel and zinc Applicable door thickness: 30-60mm (can be thickened) Color: silver Applicable type: interior and exterior door Features: waterproof, no battery Lock tongue center distance: 60nm standard Notes: Passwords are not in order, numbers cannot be repeated, and English instructions are available Keyless: No more hiding, losing, carrying, or forgetting your keys, enjoy the freedom of keyless convenience. EASY INSTALLATION: Design your own hands with the lock's unique programming code (DIY) and easily add or delete codes on the keypad. Security: The keypad provides maximum security to make your life easier. There is no risk of "low battery", the combo can have at least 4 digits (no repeats) that you can enter in any order to unlock. Applicable: Suitable for areas that need to be restricted but easy to use: offices, workshops, storage rooms, storage rooms, document storage rooms, archives. PERFECT SECURITY: High quality hard material, reinforced with a keypad lock for a safer and more flexible solution.Good quality product