The Master Lock DialSpeed Padlock

The Master Lock DialSpeed Padlock ($25) uses an electronic directional interface in lieu of a traditional combination wheel, letting you program multiple personalized codes and access a permanent backup master code should you ever forget yours — and boy would that have come in handy in high school. Other features include a boron carbide shackle, a wide metal body that can be opened with one hand, and a battery good for five years of life.