The Master Lock 5406D Set Your Own Combination Portable Lock Box features a 2-3/4in (70mm) wide metal body for durability. The shackle design offers over the door mounting for convenience. Lock box features a set your own 3-digit combination keyless entry for convenience and increased security. The flexible cover protects combination dials from weather dirt and grime; and vinyl coated shackle prevents scratching. The Limited Lifetime Warranty provides peace of mind from a brand you know and can trust.