The Master Lock No. 5424D Portable Light-Up Dial Lock Box features a 2-7/8in (72mm) wide metal body for durability. The shackle design offers over the door mounting for convenience. The large, easy to read light-up dials, combined with resettable combination functionality, provide a secure storage location for spare keys and access cards. The Limited One Year Warranty provides peace of mind from a brand you can trust.