Most people are familiar with the standard keyed padlock. You know, the kind with a big metal shackle and body, and a keyhole that you insert a key into to unlock. These are great for outdoor use, but when it comes to indoor use, they can be a bit of a pain. That's where the Master Lock 643DWD comes in. This indoor padlock is best used for cabinets and school, employee, athletic, and indoor storage lockers. It features a set your own four letter combination lock for easy combination recall. And at 1-9/16 inches wide, it's just the right size for most applications.