The Master Lock 4400D Bluetooth Keyless Padlock offers secure, key-free access using your smartphone. Through the Master Lock Vault app, users can unlock, monitor, and share access permissions with others. The durable metal body and boron alloy shackle provide strong resistance against cutting and tampering, while anti-shim technology enhances security. A backup directional keypad code ensures access even when a phone is unavailable. Ideal for lockers, storage units, toolboxes, and indoor security applications.