The Master Lock No. 4401EURLHENT Bluetooth® Padlock features a 56mm wide metal body for durability. The 9mm diameter shackle offers 51mm vertical clearance and is made of boron alloy, offering maximum resistance to cutting and sawing. The Master Lock Vault Enterprise system is designed to support Many Locks and Many Users with unmatched security, simplicity and accountability. Administrators control individual or system-wide lock access with our convenient web interface, while users enjoy simple, secure access to assigned locks or lock boxes.