Bluetooth Smart Padlock, Features 1-29/32" Wide Metal Body For Durability, 9/32" Diameter Shackle Offers 7/8" Vertical Clearance, Made Of Boron Alloy Offering Maximum Resistance To Cutting & Sawing, Use Your Smartphone To Open Your Lock With The Free Master Lock Vault Locks App, Never Worry About A Forgotten Combination, Share Access With Others Temporary Or Permanent, Share 24/7 Access Or Limit To Days Or Nights, Monitor Access History & Receive Tamper Alerts, Backup Access Using Directional Code On Lock Keypad, Low Battery Notification & Reminder On Padlock & In App, Comes With Easy To Replace CR2450 Battery, Battery Jump Allows For Temporary Access If Battery Dies While Locked, Locker Mode Setting Allows For Storage Inside A Locker, Compact Footprint Fits Most Lockers.