Ivation Smart Bluetooth Wireless Electronic Padlock Metal 3 and a &frac12; Inch &ndash; Works w/iOS & Android Phones &ndash; sheds, safety deposit boxes, lockers & more the ultimate in security &ndash; Control your Lock from your Phone - Silver Heavy Duty Metal Construction & Keyless Design Thwarts Lock Picking Attempts One-Touch Unlocking Means No Keys to Carry & No Combinations to Memorize Dual Operating Modes  Manual & Automatic  Offer a Choice of Convenience Latest-Generation Bluetooth Connectivity Ensures Reliability & Improved Security Included Single Cell Button Batteries Last up to 1 Year & Are Easily Replaceable